Msnbc and other channels in my Basic cable package

I'm having the same problem with MSNBC, but have recently discovered that ALL of the channels included in my Basic cable package provided by my HOA disappear for several days, then suddenly reappear for four or five days. I've spent two hours on the phone with tech, to no avail. I've rebooted my cable box, checked connections, etc. This must be some other problem. I sure wish Comcast would fix it!