10 Or G - Product damaged while providing service

My device is Tenor G(**or G) and I was request service through online website of tenor. My device is not in warranty. earlier I had a problem of speaker and mic of my device so I request service on ** sept ****, the product was delivered on **st after service. After the delivery of product I check that display is not working , and also the device is bended from middle, before that my device had no problem except speaker which I complain them. After the delivery of first service , display is not working. I called them, they told ,me you have to resend the device through raising a new request, So I raised a request of that matter on ** sept ****. After receiving my device they ask me to pay the amount of display ****rs for the issue which they done themselves, Now tell me, why I will pay for the issue which I faced after their service, Kindly investigate the whole matter. I'm sure they changed my part or drop my device while servicing. This is totally doing fraud in the name of service. I also sent them videos of the problem which I got after deliver. Right now my device in their service center, and they are denying for giving service, they told me to u have to pay first for it.