Changing the goalposts

I am really annoyed with Fedhealth. I am on one of their plans and take Statins (Vusor 40mgs) Two thirds of the way through the contract year they universally decide to increase my share of the cost. Surely that is not only breach of contract but is also a breach of "Treating customers fairly" When I tried to change the medicine to an alternative my cardiologist required me to take 80 mgs of the replacement statin. The person in Chronic health department advised "Can't do as it only comes in 10mgs, 20 mgs or 40 mgs" surely he should have realized I would then require double the amount of tablets. All I received was a completely unhelpful response now requiring letters of motivation and blood results etc. Do Fedhealth really expect me to believe that they actually have my best interests in mind and that I am "Part of the Fedhealth family" I think not!!