How is this fair

I am so disappointed with this company. Our premium is increasing yet again. When I called they gave me a better deal. But the instalment can only be adjusted in June how is this possible we are in April. The feedback I'm getting is that the debit orders for May has already been put in the system the 15th of April and cannot be changed this is impossible why can't they just put my account in a credit. They want you to pay the extra amount. Now if I want to cancel I need to give a calendar months notice which means I need to still pay the increase amount but my subscription will be canceld immediately WHY must I pay for a service that I will not be receiving.