HP Service Center Needs Service

We recently took an HP laptop to find out if they can upgrade it to an M.2 drive as we tried but it refused to boot form the drive. When we got to the counter we asked the two ladies there and they said the upgrade would be R450. and we continuously asked them about the amount and they said yes R450 for the upgrade, so we booked the laptop in. A week later we get an email for a quotation of the labor and parts cost and we were not informed about these costs. Very poor service from HP and it's service center. Wouldn't buy an HP laptop in future again.