Game selling customers sub standard goods

I had bought an Alva gas heater in May 2020 at Game in Baywest Mall as it was nearing the winter season and thought it would be a great investment only for the heater to give in now in August. I took it into the store on the 20th August and I had no slip but I had bought it on account and I was told they changed systems but because I had the date they could help with requesting a slip and the lady assisting me at customer service was Elizabeth and I was then told once they receive they slip they would take it for repairs. It would take 2 - 3 days to get the slip and then they would send it through for repairs and that would take 21 days. I obviously wasn't happy with that as I bought the heater for a reason , to keep my family warm during winter and it was terribly cold that particular week here in PE as well. I even requested to speak to the store manager Mr May and he was called and came to speak to me and he apologised and I was told the 21 days is just a formality and worst case scenario but they would call me back within the week to advise of a way forward needless to say I'm on this platform complaining because I haven't been called , no courtesy call at all to give me an update on my heater. I'm extremely disappointed in this company as I particularly have an account with them which means they debit my account on a monthly basis but they can sell me sub standard goods and then have the audacity to not even give me a call to give me an update on what is happening. I need a new heater and I'm not willing to take back that old heater now because clearly there is a lot wrong with it and I don't expect something that I bought in May to have already broken down in August