Trying to get 2 collections off my credit report. Old utilities.

I am trying to get 2 collection accounts off of my husbands credit report. They are both from old utility companies. These debts are 2 1/2 years old and under $300 total, but we are trying to get a mortgage and were told getting those removed would help. His score is around a 560 currently. We have wrote the letters offering to pay in full in exchange for deletion. We received letters back stating that they can not do that because it is against their policies. Where do we go from here? We have also tried the original creditor for 1 account (NYSEG)
We had success with 1 other collection agency using the same letters.
-------------------------
I have found utilities to be alomost impossible to get things off
Sounds like you hit the end of the raid there
Get new good credit for 1-2 years and your score will improve.