Return Installed Door/Window Sensors

At the advice of a contracted Xfinity technician I went from a wired Xfinity home system to a wireless Xfinity home system. After 3 weeks, I have found that the sensors do not work well. When one door closes, the air pressure makes another door sensor say that door is open when it is not closed, sometimes, that same door randomly says the door is open when it iis closed, and you can slightly close a door, not all the way and a sensor says the door is closed or vice versa. When I am away from home, some of the issues have caused a triggered alarm which registers as a false alarm. I also recently found out that I could have continued to use my wired system which is not what 2 of your technicians told me. I feel like I have been taken advantage of so that they could make a sale. I trusted them to tell me what was best for me and my home. For this reason, I would like to remove the sensors and return them for a refund. I called Xfinity home customer service and after being transferred around a couple of times, no one was able to definitively tell me how to return the equipment. Please let me know how to return the equipment, cancel service and receive a refund.