That is a really good price for an ExPed. I hope you will be able to trade for the one you want.
I have an ExPed Downmat Lite 5M, which is full-width. I suspect it is the one you were probably looking for. It has served me well now for 3 (very full) seasons kayaking and backpacking. I’ll keep an eye out for another one for you. I’ve seen a few go by on EBay. They’re not easy to come by and typically get posted for reasons similar to yours.
For the curious, I have not had any delamination issues. I have been careful to keep my mat out of hot cars and tents. The face fabric is a reasonable balance between tough and light. Make sure you don’t have a knife or spork in your pockets when going to bed.