Not happy with the 4 computers I have

I bought a computer from dell thinking that it was going to be good, after 15 days the touch pad stopped working, called them they had me send out my computer and they fixed it. No biggie, right? I did this another time since this computer had the same problems. Then I got the third one and it had the same problems, but I was over the 30 days. So, after 2 months of back and forth with them I sent it in and had to wait another two months for my refund. Then in September of this year I bought a 2 in 1 laptop from them for 1700 and then some, now in October and December I am having the same problems that I had with my old laptops as this one. It also lags and freezes 70 percent of the time that I use it. They will not give me a new computer or a refund. They want to fix it since it is after the 30 days, but all four of my computers form dells have had these issues. I thought dell would have been better than this especially since the prices are so high. Do not recommend. I would just like a new computer or a refund, am not happy with these services at all. Overall, so far, I spent about 6 hours on the phone with them trying different things for my computer to be "fine"