How can I fix my HTC One M9?

[Philip Valkov]

Ok so I'm an android noob and my HTC One M9 is soft bricked, I'm not even sure if it can be fixed. It has (had) android 4.4.2, TWRP and it is unlocked. It all started because my phone randomly stopped booting up, it started freezing at the HTC logo. After trying a lot of things and nothing worked I decided to do a factory reset, but I accidentally deleted my whole OS from my recovery. I decided to flash a new ROM and I downloaded the latest version of ViperOneM9. I flashed it from my recovery, the installation went smooth with no errors. When I tried to start my phone it booted only to bootloader. I tried reinstalling the ROM several times but it didn't fix it. I read on another forum that I should update my recovery (it was an older version, maybe 2.8.7.0, I'm not sure). I downoaded the latest version and flashed it from my old recovery. After that my recovery became inaccessible as well - it says "Failed to boot to recovery mode. Press volume up or down to back to menu". I tried installing several different versions of TWRP with fastboot but none worked. I decided not to mess with my phone anymore, so I took it to a repair shop. They couldn't fix it, I just got my phone back from them. I don't know what they tried, but everything is the same- phone can't boot up, can't access recovery mode. . Can someone please help?