I bought Archer mr600 last December 2019 and after almost 2 years. It suddenly stops recognizing sim cards. I've tried contacting local TPlink distributor here in my country, but to no avail, they only accepting items with 1 year warranty. 

I just want to ask if there's any tutorial or guides that I follow, at least I can check if there's any problem with the modem; or this modem is now for disposal?