False advertising and very bad customer relations

Bought a shower door from Carrim in Van Der Hof road. Box and invoice display 900×900, but at time of installation it was found it is 870x870. When I phone, the sales manager inform me it is 870 and he cannot take it back, as I drilled it. It came pre drilled, the next was they cannot come and collect it, he don't have a truck available. The bottom line is, the door was sold as 900x900 and I am stuck with a 870x870.