Debit order doubled without permission

Discovery changed my plan without my knowledge from Key Care Start to Classic and deducted double the premium I normally pay. How is this possible and if you call them, they say but sir you must have requested it....What a joke.

Why will I who salary did not double suddenly select a plan with double my previous plan?

Now it is long stories to get my money back. Corporate have billions and do not care about my limited funds and budgets.

Please sort this out as I see this a *****.