Hi Ishan Singla,
I'm sorry that you had to go through this experience during the development phase of your startup or during an evaluation.
As far as a solution for costs that have already been incurred is concerned, the support ticket that has already been created is a good solution. Only Microsoft can decide whether they have a solution for you.
In future, care should be taken to only buy products in the Marketplace that explicitly include cost plans from Microsoft Services or are offered under the standard Microsoft contract:
https://learn.microsoft.com/de-de/legal/marketplace/standard-contract
As there is no clear regulation regarding included Marketplace products, it is important to carefully check which usage agreements and cost models are applied to the respective services. Many third-party services are affected by costs that are NOT billed via Microsoft Credits. Please refer to the cost plan information and how billing is done. If this does not look like Azure billing, it is always advisable to contact the provider of the product in advance for further details
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