Ebay question!!! What happens if you dont pay when you click "commit to buy"?

[Kpop~VIP]

Ok, so I was checking out costumes on ebay for an anime con i was going to and I found one, but the thing is, im really short and i wanted to make a custom order but i didnt know how (first time ebay user) so i thought maybe you can change the size at the end of the order so i click buy product but when i saw the "commit to buy" i was confused but clicked it anyway and I accidently bought something and i cant cancel it, i contacted the person (no reply) and I still dont know how to change the sizes!!! > i dont want the costume anymore but what happens now? Is he going to sue me for not paying or something? Im really freaked out right now!
I havent put in any credit card/pay pal deatils.

[Thomas]

If you dont pay the fee, you will get interest charged on it, and the fee will get more expensive

[Jim]

Nothing happens, if the seller wishes to pursue it you'll get an unpaid item strike, which means nothing.
Don't worry about it, there are no fees or penalties.