Mag Fitment Disclosure

I bought a set of new mag wheels for my Golf 5 Gti from Solly's Pit Stop, the wheels originally were for a Mercedes Benz but Mohammed assured me that the wheels would fit my car without issue, when installing the wheels i noticed his employees grinding spigot rings for the wheels, when i inquired i was told that he did not have the size required. the following day i noticed the car was very unstable and had a bad vibration, i took the car to a fitment center to check the balancing, they informed me that the wheels were never balanced (Included in the mag purchase) so i had them balanced thinking this would fix the problem, the problem persisted but as the fitment center told me my tires had flat spots, i put it down to that with the intention to buy new tires the next month, i have now got the new tires and the problem is still present. As Mohummed had taken my old GTI mags as trade in on the new ones, i contacted him in order to return the faulty goods, he informed me that he had already sold my mags and that i was meant to bring them back in 7 days after purchase in order to get a refund. Mohummed has told me he would replace the mags with correctly fitted ones on the 01/05/2015.