Trojen Treadmill faulty

I have first purcahed a Trojen Treadmill in June 2015, returned it in September 2015, and got a new one, I still have a problem, when I ran the rubber mat moves to the side causing the mat to hit against the side, I don't think this is normal, can I please request that you return this product back to trojen, and can I have a new machine were I do not have problems, I am busy training for my compettions and this machine is starting to stress me out because I have to run sidewards on one side <br> <br> Please attend to my query