Medihelp has kicked my mother (with dementia) off for missing a subscription.

My mother has dementia, and in February and March this year, she removed large amounts from her bank account with my knowing, and so her Medihelp Subscriptions bounced. She does not answer her phone, and nor does she access her email effectively. I wrote to Medihelp, explaining the situation, provided my Power Of Attorney documents, and offering to pay the outstanding amounts immediately. They have refused. I find this so cruel and heartless - my mother has been a member of the scheme for decades, and this is how they treat her when she is vulnerable. I am disgusted and do not know where to turn :-(.