What happen if I exceeds my credit limit? Will the card be rejected at next transaction? Which one, mastercard/visa or amex?

Because I notice I have exceeded my outstanding balance about RM250 (both card's balances combined), but my statement balance still about RM200 before reaching their limit.

But why I can still use the card at petrol pump?

Or is the credit limit is actually separate for those two card? Let say amex/visa got RM6000 limit. Is it actually Amex RM6000, visa RM6000?

I know people are saying it is combined limit, but why I can still use my card?

Yes, I thought so because from maybank2u my outstanding balance combined exceed RM6000 (let say this is my credit limit) already. i.e: mastercard balance 4500, visa balance 1700.

I scared later I go buy groceries at Tesco end up rejected already, but now looks like it didn't happen at petrol pump.

I'm quite worried also that maybank will quietly remove the 8.88% privilege because of this and charge me usual interest.