Disappointed in Samsung Cellphone

Approximately 4 weeks ago we purchased the new Samsung Galaxy S9+ on contract. About a week ago, a whatsapp call was made on the phone. The call was completed and about 10 minutes later when we tried to use the phone again it came up with an error message "Locked by FRP block". We phone Samsung and was told it is a software error. After being referred to a very unhelpful company in Boksburg, we were sent to Samsung Store in Eastgate where I dealt with Cecelia who was very helpful and was told that the software needed to be reloaded. A week later, they have been unsuccessful and loading the software and was told that the phone has probably been "routed" and that we needed to pay for a new motherboard at a cost of about R6500.00 as it is our fault that the phone crashed!! After purchasing an R18000 cellphone which lasted for only 3 weeks, this is ridiculous. Please prove to me that I somehow damaged the phone or tell me how we can resolve this. I certainly don't expect a phone of this magnitude and cost to become nothing more than a paper weight after such a short time and being given an answer which basically translates to "tough luck". We have always purchased the latest Samsung phones and have never had problems with them before so this is extremely disappointing.