Azure Cosmos DB or Azure Blob storage?

I have data that needs to be stpored in Azure Cosmos DB or Azure blob storage. The data is about 4000 records and is a JSON structure. (See attached file "[login to view URL]") The Whitelist is replaced 3-4 times aday. The entire Whitelist will be replaced with a new JSON. The items contains a property "Id" that conflicts when I try to do Cosmaos DB. The propertie Identifier is uniq and the field i should use as Primary key in a relational database. The data is returnObject of the type Whitelist = ReturnObject<Whitelist> (See [login to view URL]) "ReturnObject<Whitelist> responceWhitelist = [login to view URL]<ReturnObject<Whitelist>>(responseContent);" I have an Intitialization that "semiworks" (see [login to view URL]) I want the cheapest possible Cosmos DB (or Azure Blob). Its just 4000 records. I need to update the whitelist items in Cosmos DB. I got stuck on the upsert command. It never did an update on existing Document. I belive the reason for this is the conflict of the property Id that is in the whitelist Item and the fact that I want to search for Identifier as primary key. Look at my [login to view URL] and make the changes needed to be able to upsert whitelist items. Need a "WhitelistItem whiteListItem = ReadWhitelist("identifier"); change the whitelistItem whit same values. Upsert the changed whitelistItem. Look at my [login to view URL] and make the changes needed to be able to upsert whitelist items. The code I tried with just creates new whitelistItems. Looks like ther is a conflict in the existing propertie ID and the Cosmos DB creating a Id for each document Is the delet of the intire collection and recreating and fill it up with a new set of whitelist items the fastest and most efficient way? I need documentation to understand the changes needed to make it possible to store data in The Cosmos DB Another solution could be to use the less expensive Azure Blob Storage. Its just 4000 document.