Thanks for letting us know about this on the community.
I have checked the line and it's showing blocked so if someone calls you they may hear the engaged tone. How many phones do you have plugged into the sockets? If you have more than one socket in use it might be best to unplug everything and just have the one phone plugged in, that way we can eliminate the equipment blocking the line.
If you have already done this then what I would like to do next is to arrange for a technician so please let me know if this is required.