Help concerning message received not sure if its from virgin

I have my mobile number linked to my father in laws account. Yesterday I had 2 messages saying to review my pre contract documents. Today I had a message from 078600649xx saying that they will be visiting my father in laws address on Tuesday. I don't want to ring the number or open up the messages as nothing should be happening on his account and i dont kniw if they are legitimate. If they rang my father in law he can't hear very well, and so could of agreed to anything. But we only saw him a couple of days ago and he said nothing.  Can someone please help. 

[MOD EDIT: number edited in case it's an innocent number being spoofed]