Unexpected raising costs for Azure Elastic Database Pool

Question

We booked an azure account in Germany with the Telekom as a reseller (due to GDPR reasons, it "sounds better" if you say to your customers you host with the Telekom than on Microsoft :-))

We have an elastic database pool:

Germany West Central, Elastic Pool, RA-GRS, vCore, General, Gen 5, 2 vCores, pay as you go, no hybrid, 32 GB

According to standard azure price lists, price calculator and documentations this should produce round about 329,23€ per month (plus reseller margin). All information I can find confirms that this cost is fixed and there is no variable part that could increase this cost.

In the first month (12 Databases, 1GB used, nearly no actual use) the cost where as expected.

In the second month (14 Databases, 2GB, not exactly sure about usage) the cost raised by 150€.

In the third month (14 Databases, 2GB, nearly no actual usage) the cost raised again by 150€.

Aside from addingh 2 databases and using 1 more GB nothing has changed. The configuration of the pool was not changed in all thoose month.

So currently we pay double the expected cost and worry that it will raise another 150€ the next month. The Telekom claimed that "there are no fixed prices with microsoft" and that the raise is because of the 2 new databases. This sounds like complete nonsense to me. They opened a ticket at Microsoft, but after 2 weeks we have still no answer.

Assuming (as they also claim) that the problem is not on the Telekom side and Microsoft really bills them an increasing amount every month, despite it should be a constant price and despite it is barely used und nothing has changed that could explain the raise, does anybody have any idea, what could cause this raising costs?

Edit 1 : This is not the "branched" Telekom Cloud Azure that was discontinued this year.

Edit 2 : Because of the reselling, all cost control tools are disabled and replaced by "ask your reseller".

Edit 3 : I'm quite sure that I understand the azure price model correctly and this is not the way it should be. My suspicion is, that there is maybe some variable cost part that under normal circumstances doesn't play a role (like eg network traffic or something like that) and that there is something special going on (like a programing error, causing an infinite loop causing querying the database over and over again, causing TBs of traffic each month. But this is not the case. The metrics show 0% IO over the last month).

Edit 4: The invoice lists 2 positions. One for the pool and one for the sql server license. There is an "amount" (a four digit number). This grows over the 3 month from 1488, to 2230 to 3156. The price for position 1 is 0,141€, the one for the license is 0,084€ per "unit". I have no idea what this unit should be nor why it is growing each month. I also have no idea while the sql server license is also billed according to this "amount". It seems like a completely different pricing model to me where pool and license are charged for something like "minutes with activity" or something like that.

Edit 5 : I just noticed a strange thing. While in the pool under configuration there is a "data max size" of 32 GB, if I look into a database of the pool under "compute+storage" there is also a slider "Data max size" (but no one for the vcores) whith shows 250GB? Whats going on here? How can the pool have 32GB max but each database 250GB max? (I'm absolutely sure I have not configured this and I don't understand how the db max can be more than the pool max). But event this could not explain the charged amount (the data max size is more or less cheap and does not increase the license costs).

Edit 6 : If I compare the numbers it seems that the unit of the billed "amount" is 0,5h (strange). The prices for pool and license are more or less exactly double the hourly prices at MS, and the amount in the first invoice (1488) is a litte bit more than double the 730h a month has. According to that we were billed for 46 days in the second and for 66 days in the third month. If it were 31,62 and 93 I would have an idea whats going on (they don't reset the counter after billing) but the numbers do not give that.

Answer 1

As it turned out, the reason for the increasing cost was a completey different single database in a different ressource group, which was accidentally booked with vCore instead of the much cheaper DTU model (at least for lower DTU numbers). Because of the "reselling situation" not only on booking the costs where not shown (so the error goes by unnoticed), but also, the cost analysis tools where not available to investigate. Additional confusion arose because the additional database in the completely different ressource group did not result in a separate invoice position (as intuitivly expected) but instead increases the already existing positions that where assumed to represent solely the other elastic pool.

I'm not sure if this question and answer is of any use for anybody - except maybe a kind of "warning" when using resellers and to undeline how importent the display of costs and the cost control tools could be.

And perhaps an additional warning about the incompetence of some of such resellers to help you investigate such a simple question.