HTC – fake product

I have brought HTC desire 820 on 30/12/2014, and i had and issue with this handset in 1 year 3 times when i visited the service centre they will take 10 more days to resolve when i visited last time they took 10 more days again and they the close the service centre for 5 more days also they given me different swap phone for my old phone in new phone also i am facing same issue from 1st day onwards if i call customer care they are saying issue with the sim card, sim card is very much active in different phones, this peoples are not ready to agree with there issue, there is huge complaints in service point with the same issue, there is no service centre nearby we should go 20km every time i am getting reply from customer care visit our service center, ban this HTC and pls help me out on issue