Phone [Q] ODIN Custom OS

I recently tried to use ODIN to reinstall Android because I felt my phone to be slow in showing up and running certain applications. I did a factory reset before that, but unfortunately it didn't solve my problem. But after installation using ODIN, my phone went into a boot loop. I tried few attempts reinstalling with ODIN but was unsuccessful. I tried even with PIT files. But after that even the bootloop stopped and there was only a black power screen which was visible. But still I was able to access Volume-up + Power + Home button combination to bring up ODIN. I agree that I shouldn't have attempted custom ROM, but still something puzzles me about Samsung Service Center.
The unfortunate thing happened when I went to Samsung Mobile Service Center I was shocked to hear that my mobile needed a LCD SCREEN REPLACEMENT. But I couldnt understand the purpose for it when there was no physical damage and LCD was working fine because, when I gave the mobile for service, I was able to access the Custom ROM installation screen through Volume-up + Power + Home button.
After their inspection, my mobile flashed only a white screen which was not present before. Now I cant access even ODIN screen. I dont understand how it can be a problem with LCD. They have said it would cost 2,200 for LCD replacement. But as I said, LCD was working fine before I gave my mobile for service as I was able to access ODIN screen.
I just had to take my mobile back without servicing, fearing more damage and charges.
I would like to know if LCD replacement should be done just because of using ODIN to install custom ROM. What can I do further? Give in the same service center or some other service center ? Pls help.