iPhone won't go back to old number!!

so my dad loses his iPhone, I take him in and get him a new one, and he maintains he needs a new number (afraid of robbers or something) now he finds his old one, and I teach him how to re-set and re-sync everything. he does it but with the wrong number. Now when I go back and sync everything with the number he WANTS it doesn't stick and we're stuck with a number no one knows except for him and I. so how do I fix this? I know I need to cancel the 'bad' number but will that fix everything (he won't let me near it so I can't experiment) thanks for the input.

how/why did att/apple give him a new number if he already had an account?

that would be where i would start, with a all to ATT

he decided he wanted a new number (I left him alone...) so anyway, with the startup having iTunes open it prompts me to go through the whole setup process (after restoring it) this is his old iPhone the new one we returned. Anyway you can choose between the two numbers since his name is on both accounts lets call them numbers Alpha and Bravo. Bravo is the new number, it works great but no one knows it rendering it useless for his buisness. number Alpha when set up on his iPhone acts perfectly, until you unplug the iPhone and try to do anything. it resets itself to number Bravo. this isn't an ATT thing except they are giving us crap about closing the account for number Bravo. any input appreciated.

i work for iPhone activations haha so by the sounds of it you can just go and get a new sim card and then resubmit as an existing customer with an upgrade with whichever account has the number he wants on it then all the work should be done and the iPhone should work again

Yeah I asked him if they had told him anything about it and his reply was "they told me to pick up a stim card from the desk but the phone was working and I didnt want another membership card." we got it all worked out, very frustrating though . thanks for all you're help!