Su-Kam - worst customer service within warranty period of su-kam ups.

I have purchased a su-kam falcon hbu ****/**vdc sine wave hups on **/**/****. Product serial no is ***b****************. My inverter is stop working on from **/**/****. I have registered a complain in su-kam customer service (Mobile no.***********) on **/**/**** vied complain reference no. *****c********. I was told the service engineer will visit in ** hours but never saw him. Also i called the customer support several times and every time they mention they will send next day (Looks like some standard script) but never saw anyone. I called the manager (Mr. Khatua, cont. No **********) of asp kolkata, su-kam service centre several times and he always responds that he will be arrange an engineer to visit my premises next day but in vain. Would like to request you to arrange someone immediately as it is very urgent in point of view. But till date(**/**/****) no action has been taken to resolve the problem.