Unresolved warranty

I purchased a laptop last year April, only for it to stop working mid July. I took it back to the shop and explained that I had misplaced my receipt but produced proof of purchase since I had swiped. They said they can retrace the receipt... It's been months and I've been going back and forth to the shop but my issue has not been dealt with, they apparently cannot trace my receipt. Worst is I get no communication until I go and enquire and this is after I produced everything they had required of me. I fear my warranty is coming to an end and I'm still stuck with a faulty laptop that I have barely even used for 4 months