I wrote a letter to cancel & ask for my deposit back. For our deposit we wrote out a check for 1/3 of it than post dated two checks for 12-20-10 & 1-20-11 for thye remaining. I sent it off post marked the 26th by certified mail & return receit. I also sent back the bag of material by certified mail & return receit. Should i put a stop payment on the two post dated checks that they have?