Missing heater, Mulbarton Pick and pay unavailable

My sister's Goldair fan heater stopped heating within in the warranty period. The manager at Pick and Pay Trade Route refused to assist her and referred her to Mulbarton. I took the heater to Mulbarton on Monday. I was infirmed by the supervisor on duty that it would be sent for repairs and to expect a call from the customer service representative that day. No call came. All calls to Mulbarton remain unanswered. Today, I finally reached a person named Noluthando, who dropped the call as I was explaining. I tried phoning repeatedly. The call goes through from the welcome recording and rings, but is picked up and quickly dropped. This is not the level of service I expect from Mulbarton, my favourite store, where I shop frequently and enjoy a pleasant interaction with staff, as well as excellent service. I am at a loss. The heater is missing, not repaired, not replaced.