Greatly disgruntled and pained

This company is greatly disorganised and greedy. I cancelled my subscription in March but still have them attempting to debit my account. Contacted customer care, they confirmed that it had indeed been cancelled but that I was still owing for one month due to the cancellation period which was not properly explained to me when I issued the cancellation. I had to request my cancellation documentation and email them several times before being transferred to finance. Made the one month's payment the finance department said I was owing and submitted proof but a debit attempt has been made again. I account is fully settled. Why am I being expected to pay for a service I no longer utilise and incurre bank charges which I will not be compensated for though I'm not at fault. I greatly regret even using Netstar services to begin with.