Gas contract renewed via third party against our wishes.

BYRON63

We are a small organisation and are to recieve a new Gas boiler under a local scheme.Contracts for the new supplier,direct debits etc were exchanged earlier this year.The current Gas supplier were informed,as our contract expired November 30,2019.
However,a third party firm contacted a colleague some months ago to extend;my colleague explained we were having a new boiler,changing supplier,and just wanted cover till end of current contract.Now, we have been told the current supplier has arranged a new contract for 3 years,till November 2022.They say it was a verbal agreement,which we disagree with strongly.Now, we face not having our new boiler,as the suppliers can't be changed at present. I've tried contacting the current supplier,been given the runaround via departments,then sent an email as they asked explaining everything,but no joy as yet.I've even asked for a recording of said phone conversation for proof. Nothing,as yet. HELP ! anyone ?? !