BAD AFTER SALES SERVICE

I bought a pressure washer in 30/11/2022. I using it for a while but it lost pressure when sparying .I took it in on the 29/8/2023 to Builders Warehouse where I bought it. The repair note is all for parts of the motor that is faulty. I just want to find out is this not suppose to be a warranty claim as they want me to pay a amount of R1960.75 for repairs to it. I spoke to the sales rep , he gave me e-mail addresses to contact according to him it was managers. I send them mails but no-one ever comes back with solution. They do not even answer mails. We always only bought Karcher products and this is first time we have issue. Would just me nice for someone to try and assist us.