Superior Asset Management

Hello. I've been getting calls on my cellphone from Superior Asset Management regarding a collection towards my wife. I've been ignoring them since my wife said she doesn't have any debts, and I thought it was one of those scams. But now I see on her credit report that the debt is there too and went to collection. We are currently trying to get a refinance on our auto loan, but we were denied because of that collection against her. The original creditor is T-Mobile and she doesn't remember having T-Mobile in the past, but at the same time she is not 100% sure, so I'm thinking of just paying it off to be able to refinance our auto loan as soon as possible. Since I heard all sort of bad things about this Superior Asset Management, my question is, what do I have to do to make sure they are going to erase the collection from my wife's credit report once I make the payment to them? Also, I heard that you should not pay by online check or phone check giving them any accounts numbers. So, what method should I use to pay? In case I want to get a detailed account of that debt from them, should I give them my address so they can send it by mail? Thank you very much. Ricardo