Shocking Service Leroy Merlin Little Falls

I purchased a Gentec Inverter from Leroy Merlin Little Falls in December, only 2 months down the line it is not working properly, they are aware that there is a problem with the brand as many of them have been returned, however they will not honor their returns policy "Buy without hesitation, return without reservation. I can wait up to 21 days for technician to look at it, I work from home so need the back up power. They refuse to refund me or even exchange for another option for which I was willing to pay in extra. They promised to call me on Monday but nothing, I have tried calling and have left messages but to no avail. I now have to purchase another inverter as I cannot work, how is this good service? I happened to be in another branch and explained the situation to one of their staff, and he said that an arrangement could be made for a customer, and all the reasons that they had given for the failure of the product, basically my router drained the power etc. were incorr. I now have to incurr additional expense and cannot even get a response from them and they have my inverter sitting there.