HiFi review: defy stove

My 81 year old Granny bought a stove from HI Fi Corporation in Kenilworth Centre on July 30th. Where she was requested to give the receipt back when the stove was collected. The stove started acting up In October now they saying the can't assist without a receipt of purchase that they took back. In October calls were logged for technicians to come out till date nobody came, when calling the branch you hold for longer than 30 minutes and they drop the call in your ears. Going into the branch they say the person who logged your call no longer works here and she didn't do her job, this service sucks my granny now needs to struggle to get help after you took her money now you giving her bad service it's disgusting