did some really dumb purchases ???

i have a suggestion that if u could undo a purchase after u make 1... it wouldnt have 2 be 4 a long period of time only be4 u use it cuz sometimes u hit the wrong button at the shop and then ur screwed ...... happened 2 my with coupons i wanted 2 exchange my coupons and made a wrong click and now im stuck with an mp5-adv 4 90 days (it happened 20 days ago and i still havent used the mp5) so i lost 10 coupons 4 sth i dont want and i dont use so it would be nice if this happens