What do you mean by "different"?
Different to what?
Your phone number should be listed on your My48 account here:
Are you saying that a different number to that one appears at the callee end when you make a call?
Or do you mean that you had a number with a different provider but that isn't the one that is used on 48?
In that case you need to port your old number over to 48 from your old provider.
See here for instructions on how to do this:
If you need to contact 48 support about this then see the links in my signature below.
