Hub Phone problems

Normally my Hub phone is ok but over the past few weeks been receiving phone calls but when I answer there is nobody there. Altogether I have had 19 of these and they are all blocked numbers so no idea who is phoning, nobody apart from one family member has my number and quite often after the phone call my hub drops connection and I have to reboot hub.

Any ideas please

Strange, call up BT and go to nuisance calls dept they will tell you.

Thanks Paul