Hi ejayne72
It is an intimidation tactic used by insurance companies, I would advise you to seek help from a Wlefare Rights Organisation.
If you receive CB ESA then ignore the what the bus company have informed you, if you receive IR ESA then seek advice: You can find your local Welfare Rights Organisation to help you with advice by clicking on the link below and putting in your post code, it will then come up with a MAP with a list of agencies.
advicelocal.uk .
Gary