I have topped up with 30 euro I still have no credit

[dalyer]

What do you mean by "credit" here? 

Is the €30 appearing on your My48 account as cash credit?

If so do you mean membership which you need to buy separately using this cash credit or your card?

See here for an explanation:

https://community.48.ie/t5/The-Knowledgebase/All-About-Memberships-and-Payments/ta-p/53105