iPhone 6 Unable to hear through receiver

I am using iPhone 6 happily from last 3 years untill I upgraded to iOS11. Immediately after a month my front receiver got a fault and need to get replaced. I also replaced my batter. Today, The receiver fault is again back in my phone. It raises question on quality of parts Apple use. My phone response is slow, not like an iPhone anymore. The battery drains out very fast. I visited Apple Genius Bar but they are not keen in helping me, they are more interested to sell me iPhone X. Anyone else facing this issue? Please advise me? Else I am planning bid adieu to iPhone forever as I never expected them to make a product which will stop working after three years without a valid reason and they are least helpful.