I’m not able to preview any cameras, not new or old cameras

For more than seven years I’ve had Xfinity Home.  Over the course of time, I’ve added a total of four cameras, two motion sensors, and eight window and door sensors. I do really appreciate having a monitored security system.  That being said, once I added the two Xcam outside I’ve not been able to preview them. I’ve been able to preview the two older cameras even though my touchscreen freezes and reboots at odd times.  I’ve accidentally set off my alarm by opening up the patio door early in the morning. I went to the touchscreen and tried to disarm the system but it was frozen. Thus needed to run down two flights of steps to the keypad on the lower level.  I called after that and tried to get the point across that something was wrong with the touchscreen but amazingly it’s still in my house.  Now, I can ‘t preview any camera on the touchscreen. An appointment is scheduled for tomorrow.  A tech scheduled  and said I need the newer touchscreen. Fine, I can agree with that, but still I’m contacted a few times telling me that my system was fixed and it should work now, please check it. It was checked, still the issue persists. That was twice yesterday.  Today, I get repeated texts about it. Xfinity, please send the tech to replace the touchscreen. It’s seven years old. No one keeps a tablet or computer seven years that is required to give valuable information about a security system. Sorry, if it’s a rant. I’ve had Xfinity in my home for over 23 years. What’s up with this stuff pulled on loyal customers.  My patience is tried. Sorry again.