Sinotec Smart TV 10 inch from Lewis stores, don't work!!

I bought a brand new Sinotec smart TV, but it's doesn't want to accept the terms and conditions of the TV so it can't log in, I only watch Netflix and YouTube because they came with the TV but I want download any other apps because the TV doesn't want to sign on, iv complaint about this TV from day 1 it gave me problems, they kept saying the problem is on the "complains" or they keep on giving me lame excuses recently they said they will come and exchange the TV but they didn't when I call the manager they keep on saying she is not available I'm not a happy client since I'm paying for that TV and I'm also paying for their insurances but they cant help me with a TV problem that came with, I'm out of resources on how I should complain to them so I'm hoping you guys can help me with this matter