Divorce decree vs. divorce petition - when settlement varies

If a clause about settlement terms was included in the petition for divorce or other divorce documents, but is NOT included in or referenced to in the actual [finalized] decree, is it upholdable? My ex and I agreed I would get his name off the mortgage to our house (quit-claimed to me) after the divorce was final. We marked "does not apply" on the decree to Real Property Judgment, and didn't include that stipulation anywhere else in the decree. I was delayed in complying with that, so in retribution, he has defaulted on his maintenance payments to me. I now have the paperwork to update the mortgage, but it will cost me nearly $2000 to do so. Do I have to? Can I force him to pay the bank fees?? Thanks.