I want my refund

I am extremely dissatisfied with how my account has been handled following the cancellation of my data contract. I cancelled my contract in store and was clearly told that there would be no cancellation fees. The online support team confirmed this to me on the same day. Despite this, I later received an email stating that I had to pay for January. I was then told by the online team that I would be removed from the January billing, yet money was still taken from my account. Both in-store staff and the online team advised that I should receive a refund. Instead, I am now being told that I must pay additional charges, even though I received no data or service for December or January. It is unacceptable to charge a customer for services that were cancelled and never provided. I expect this issue to be resolved immediately, a full refund issued, and written confirmation that no further payments will be taken.