This is entirely the fault of the service you are using. Some services manually confirm transactions, others wait for many confirmations. It is unusual these days for services to require more than 3 confirmations on the Bitcoin network though.
Refer to your tx ID on the Bitcoin blockchain itself (using a public explorer like Blockchair). If there are more than 3 confirmations there, you should get in touch with your service.
If the confirmation number already exceeds required numbers, but balance is not credited. Please open support ticket to contact their customer support. If they say the mistake is from user, it is a lie. That service can scam users.
The bad scam is make your second deposit to help the first deposit being credited to balance. It is their double scam.