I receive calls but then a heavy machinery sound plays over and after clicking 1 to answer the call and cannot connect or talk.

I receive calls but then a heavy machinery sound plays over soon after clicking (1) to answer the call, and cannot connect or talk, as I can hear only that heavy noice, if they leave voice mail; only that sound is recorded. This is happening for the last 9 months. Receiving calls directly or through the app does not matter. Pls advice any one? Called weebly tech support 3 times. They cud not solve the problem yet.