I bought my Vive almost immediately after it came out. It was fantastic from the get go and I loved sharing it with everyone.
A little under a year in, I started getting headset blackouts. I contacted customer service and was led through troubleshooting steps that involved hours and hours of unplugging and replugging cables, reinstalling drivers, and changing settings. It was two months of this before they finally accepted that they would need to offer me repair services.
I packaged up my Vive headset very carefully in a well padded box and sent it to HTC per their instructions. I received it back weeks later in a box that had a single sheet of bubble wrap loosely put inside. There was no paperwork to indicate what had been done, and when I plugged the unit back in it still had exactly the same problem.
I emailed support to let them know the issue had persisted but received no response. I was so fed up at that point that I just gave up.
It's been months and I would really like to actually be able to use the $800 unit I bought but now that support is actually responding to me again they're telling me it's out of warranty and I'll have to pay $270 to get it repaired. No one along this entire process has been able to tell me what repair work, if any, was actually done on the unit and I've received no apology for the shoddy way it was packaged and returned to me.
Based on this experience, I'll never buy an HTC product again, and will be warning as many people as I can about their awful support process. I was an early adopter and booster on this technology and they've treated me like absolute garbage.
You are not alone here, I am dealing with the exact same problem as we speak.
Broken controller out of the box upon purchase, sent it in under warranty (still had to pay $10 out of my own pocket for priority mail).
I sent in 2 controllers. They only sent back 1 with no letter or anything telling me what they've done, I had to contact them again myself. The other one is still missing, I'm in the process of trying to get that back still.
This has been in June 2018, it is almost October and it's been a battle ever since. If I don't get some kind of resolution soon, I'm going to put HTC Vive on blast and make sure all the gaming journalists and social media know how bad HTC Vive have been treating us. I have all the pictures and transcripts from my interactions I need from them.