iPhone 4 ear piece replacement still doesn't work

[R&J Whitetails]

Hi thanks for reading and helping me out. So the ear piece on my iphone 4 is getting bad and I ordered a new one the other week and after I installed it I couldn't hear any thing on it. I thought I must have got a bad speaker so I ordered another new one from another company and installed that one tonight and that one won't work either. I can put my old one back in and it works like it did when I took it out. What am I doing wrong??? Thanks