Realy Bad service

<p>This people make seat covers for vehicles. I ordered 2 sets for 2 double ldv's from day, they give me the quatation and tell me it took 6weeks after they received proohf of payment. After 6 weeks I called, they were finished with 1 set and havent started with another 1. Another 2 weeks wnt by and I received it. 1set was incomplete and the other 1 short a securing strap. The holes for the headrests are off centre. They sent me the missing part and the 1 with securing strap but now they are not comming back about the bad work they have done on it. What can I do to force these people to get what I paid for?</p>