Possible wiring issue

So our landline's not been working for a few months now. We never use it to call out hence the lack of urgency but we're paying for it so may as well get it sorted.

Phone has been displaying 'check connection' and has no dial tone. If we ring the landline from our mobile it rings on the mobile but not on the landline. The landline does make a click sound though and registers a missed call. We can't answer the call regardless and it won't go to the answer machine.

So something is getting through but not properly. Managed to get hold of another phone but doesn't ring either so I'm assuming it's a wiring issue

The phone is plugged into the wall and hasn't changed for the 15 years we've been in the property. The only other socket I can find in the house (all this was in place when we moved in) looks like just a standard socket and that's never worked

I'm assuming it's engineer time but would it be easier to just switch over to VOIP through the router? Would save a lot of hassle and it's going to have to happen soon anyway.