how can i find balance of CC

[Mayson]

There are two approaches here in general. I'll explain.
First approach (safe): Some banks provide an automated phone prompt for you to lookup the available credit on credit cards requiring only the card number and zip code (credit cards only.) An example of this would Visa Chase Credit (there are also a few other bins from other banks that allow this -- do your research.) The same is also true for debit cards, but they always require either PIN or last 4 of SSN to reveal the account balance. So it takes a little more work for the debit cards/checking accounts, but it is also possible. With this method, the risk of killing the card is virtually ZERO. Literally.
Second approach (risky): You could use any checking service that allows you to set your authorization amount (luxchecker.pm allows this) to see whether or not the card has that amount available for usage. But the results here aren't always correct, and here's why: If you submit an authorization for $500 and the authorization is declined, that could either mean that the card indeed doesn't have the much credit/balance available, OR it could mean that the authorization attempt killed the card. So that's the risk here. My suggestion here is, should you decide to take the 2nd approach, is to create your own merchant account (read more into that) and use your own merchant account to submit authorization requests and then void the sale. This third approach is less risky because the banks have not seen much activity from your new merchant account yet. Once your merchant account becomes flagged with different banks as a result of your many authorization requests, you can create a different merchant account to continue.
Hope I have explained everything clearly to you.
Good luck.