Metro selling damaged goods to consumers

In April 2015 I bought a Singer sewing machine from Metro. Within 6 months it broke and I returned it to be fixed since it was still under guarantee. Metro claimed to have fixed it but within 1 day of use the machine broke again with the same problem. I took the machine back and the sales person Million and the manager supposedly took the machine to Singer manufacturer. Apparently Singer returned the machine claiming the there was nothing wrong with the machine and that I do not know how to use a sewing machine. I have been sewing for 3 years professionally. I requested a refund but the Manager refused to refund me and told me to take the issue up with Singer even though the machine was still under warranty. They gave my machine back and I have paid for a brand new machine that is not working. Please give my money back.