CBCS collecting via 3rd party?

Hi,everyone. I ran across your site today after receiving a letter from a company called CBCS. After searching through your forums, I see that most of you are familiar with this company. Anyway... I received a letter from CBCS today who are trying to collect for asset acceptance llc, who I believe is trying to collect for Southwestern Bell Telephone (name of original creditor on the letter). It's a Settlement Offer letter from them for about 50% of what they claim I owe. Regardless, I do not believe I owe this to them (I don't recall ever having a Southwestern Bell account at all). The problem I may face before I send off a dispute letter is that my father and I both have the same name. Of course, at one time we did have the same address and he did have Southwestern Bell as a telephone carrier for his house (even when I lived there). I'd like to find your template in which to ask them for validation of this account (I've tried several searches and can't seem to find one that really fits). It's weird due to the fact that it's a collection agency trying to collect for a collection agency. If/when I receive a response and they try to verify if it is or is not me, due to my father and I having the same name... how do I show proof that it's not me? Or, how would I go about disputing my identity if it is not me? I appreciate all your help. Thanks.

Budmas