When We First Bout Our House It Was Mortgaged Through Wachovia

which we had no complains, then wachovia sold our mortgage to citi, who immeidatlyh tried to raise our interest rate. in our contract it states that our interest rate could not go up more than 1/4% a year with a cap at 6%. Citi immeidatly indicated they knew nothing of this and wouild have to examine our mortgage papers, when the next payement came in the mail it was at the correct rate. Shortly after my husband was severly injured in auto accident and i am on SSDI so our bills quickly added up. Yes our house payement got behind, however when were able to obtain $15,000 dollars to give to citi they refused the money and said it was too late. I feel they did this because they new our house was worth more than the mortgage owed on it. Is there anything we can do about this?