SELL BAD INVERTERS

I bought a sine wave inverter from the EDENVALE/MODDERFONTEIN branch in 2020. Around 7 months ago I took it back as it was running flat quickly. The told me to buy a new batter which I did. When I got home I put the inverter on charge for a few weeks then started to run my tv off of it. After 4 months and all this load shedding started I would use it late evening if we went down and the battery onlly last 50 minutes.. As I PSS is some distance away I didn't rust to talk it back, load shedding only 2 hours and 90 % of the time I was not home. I took it back two weeks ago and get told it is the battery , seriously the battery is not old and has hardly been used. They tell me it only last 500 uses, now we have not had 500 hours of load shedding or they has not been load shedding for 500 times, anyway not they want to sell me a battery that costs almost 8000 rand which is what I Paid for the inverter :-( I took back the inverter as seriously they are just making a quick turn over and guess what, the battery they gave me back does not work ?? They don't give a hoot, i wonder why it does not work? Cause they cant make money from me...We have 3 inverters at work we bought at makro 7 years back and we have not replaced one battery !!! I advise people to go to Makro and builders and stop this company milking the little people!