Follow their instructions and post there if it fails.
Here I just send folk back to the carriers service center to have the tech reflash the phone.
Why? Because folk usually won't pay for the work so I found it best to advise they take it to the shop.
So I rooted my phone before and I wanted to unroot it back. I think I did something wrong and now my phone is stuck in the bootloader menu and I can't get it to boot. Also, it seems like it doesn't connect to the pc via usb because when I tried running the fastboot devices command in cmd nothing was found. Another thing I tried was the RUU but it just told me to check if my phone is connected.
Please help guys I cannot use my phone at all and I tried almost everything to fix it !
(If you need any other information just ask)