first off what is your pc make and model and what type of issue are you having. if your in the us look at your state lemon law and contact your credit card some of them extend the warranty of the product. also look at your sales paperwork some people by the extra insurance to cover more then one year of warranty. if the shop is a certified repair depo or they have a tech that taken the vendor traing classes and can do warranty work on pc and laptops of vendors. they should have replace a few parts in a cross ship to see if they could find the part that was failing. most good repair shops will have know good spare power supply..ram..and hard drives to help rule out a part causing issues. did ether shop on there report say what failed and why it could not be repaired?? most mom and pop shops when they see green horns will say this cant be fix or it going to cost more to fix then buying my unit over here. most shops love waranty repais as they get paid for the parts and there time at a fix rate. most vendor have small program you log into the vendor repair put in the spare part number of the part..the ser# and the ser# of your pc and it orders the part for the repair tech..all the repair tech has to do is then send the bad part in in cross ship. after the unit is repaired they put in a billable ticket for the total hours..less then 30 days later a check is cut to the repair shop.
i would google to see if the pc or laptop was a lemon and if there were any recalls or class action lawsuit..i would contact the vendor costomer service rep and ask for the local vp rep or manager for your country. be nice but tell him that you have one of there products that become unrepairable..from two shops and you like to ether repalce it with same unti if they still make that computer or a refund.if you have to send registered letter to higher up and email and keep the info of who you sent it to. the last thing you can do is file in the us a small claims..