Received an account 1 YEAR after elledged service

Received a call this morning from CMS accounts department form no ***. The reason for the call they said was to inform me of an outstanding account for a alleged call out fee dated back to MARCH 2015. We are 17days away from MARCH 2016, today is the first I am notified of an outstanding amount from 1 YEAR ago. If this is not ridiculous enough when I asked why they never queried this before today (it' s been a year since the alleged service) I am told they have sent \a\" statement but they cannot explain why I never received anything to this effect despite the fact that they have my correct email address and I receive my monthly CMS reactions statement/Invoice from them. Told them to send me information and proof of the callout, the proof that I just received is a email dated today quoting an acc no and amount owning: the rest of the mail reading \" Please note that accounts are due and payable on or before the first day of the month with a grace period of seven days, no information or proof of the alleged service. Am I expected to pay because you claim there was a call out 1 YEAR ago and since then an outstanding balance due *sic* NEW SECURITY COMPANY IS THE WAY TO GO!"