Dropped Calls

Calls on my landline have been dropping calls for the last month. I have tried tech support with no help. Tried new phones, rebooting modem and nothing helps. A tech was sent out to replace modem and when I explained problem he said many customers are having this problem, it is a glitch in the modems software, and even replacing with new will not help as the glitch is in there as well, and no idea when it will be fixed.  I am so upset that I do not have a reliable land line. Can the moderator shed on this problem?