I'm always dubious about making contact, as if it confirms something to them, that I am here etc when currently they have no idea who they are messaging or rather who they intend to message is in fact still at that number.
Your wording reads ideal to me so I think I will send them a letter, question is can I write to them without being threatening myself, that's a hard one but I will try.
We have a truecall system on it's way, that asks people to press a button so we know it is a person before our phone rings through to us, it records 140 hours of calls you can download to your pc and you can exclude a lot of numbers that can get through like out of area, international and numbers like 02392 all theirs come from, and you can set it to tell the caller to say their name, the system rings through to us, we hear the name and then choose if to accept the call or not, it can't get here quick enough!
Credit ref I don't check as I never have any credit, cards I pay off by DD in full every month, all suppliers are paid on time, all utilities are on DD etc etc etc, in fact I use credit so little I can never get any easily, last time and only time in about 20 years is when I bought my last car, I have to show why my credit rating is so bad, ie as I never have any, then I can get it.
That's another joker too hey, experian, give your details for a free month, just to do what always happens which is forget to cancel it, and you've been done.
Many thanks!