Exchange without till slip

Having beeen buying things there lately for soo many years.. But now all of a sudden i cant exchange anything without a till slip what is that.. Im stuck with sdhoes that has a tag on and i cand get a correct size all because of a till slil.. Bought myself earfones 2wks ago but they hv stoped working and i hv a box and everything still they wont take it bk.. I hv bought clothes and other things in all other shop but PeP stores is a joke