What do you mean "topped up your credit"?
Did you buy a membership?
Or an add-on?
Or topup your cash credit balance?
What does your My History page say about recent payments/purchases/topups?
What does your My 48 page say about your membership status, expiry date and membership/add-on allowance balances?
What kind of call(s) are you trying to make?
Irish regular landline?
Special landline (e.g. 1850, 1890 etc.)?
Hope this helps.