Does anyone have any travel agent advice?

Due to a mistake/stupidity on my part, my balance payment of my holiday with Thomson is due a week before i get paid.I called Thomson to explain and was told they could give me 24 hours after the due date, but after that they would cancel my booking.I'm now in the process of trying to get help with paying this holiday but in the worst case scenario and i can't pay on due date,does anyone know if Thomson may be flexible and give me the extra week as i don't have a problem paying then?