Useless service from Builders warehouse & Lawnstar

Bought a Lawnstar trimmer at builders warehouse. Used it once and then it started smoking. Sent it back and they said they can't replace it but must take it to Lawnstar for check up. It's over a month now and I have not recieved not even a call to update me on the progress. On the other end, I'm now paying a garden service to cut my grass but yet I forked out money to buy my own grass trimmer. Disgusted in both builders warehouse and Lawnstar.