Fax-On-Demand Software & implementation

Dear Sir

This application is for a Call Center

a) The user calls in and respond to recorded messages
he will enter account no ( provided by us) by telephone keypad

b) we have to check his balance if he has balance in his account

c) If he has balance he will enter the date,document no and fax no
where he wants the document to be faxed.
WE can also provide him with the list of document

d) The fax will be send to him and his account will be debited

Is there anyone who has this type or software or can implement such software

Can you suggest me an application and the cost detail.

Regards
MUstafa