The problem we are facing is that we need to track this transaction and show in User Panel how many CVB coin someone has bought.
If each user has to register on your site, you can simply assign one deposit address for each customer. Then it is trivial to track how much coins have been bought by whom.
If you are offering this without a registration, it will get a more tricky. In this case you will need to combine multiple techniques (cookies, ip-/browser- tracking, blockchain analysis, etc..). But note that if you are going to track your user with cookies or browser information you will need to provide all necessary information (regarding the General Data Protection Regulation (GDPR)) to your customer.
If you don't do this you will get quite a lot legal trouble.
The problem is, which online wallet can we integrate with our website to track this kind of information,
Online wallet? You don't need any online wallet for this purpose. Thats completely unrelated to your actual problem.