Hi Kathy, Sorry to hear about the annoying calls. I can only imagine how much of a pain it is to be continually called by a fax machine. We do have a feature called Call Screen that would allow you to block a number, unfortunately it does not work to block ALL numbers, so this may not work for you. Honestly your best bet is to keep trying to fax them back if this is an option for you. Hopefully you can eventually get through and pass them the message. From my experience these extremely busy lines are often easier to get through to in the evening or weekend, so you can maybe try contacting them at that time. If you don't have access to a fax machine in the evenings to reach out to them you can always contact our technical support group and we can send the fax on your behalf. I hope this helps.