Charged for a cancelled service.

I cancelled a domain months ago, I got confirmation, so took as sorted. Last week I was invoices for the domain service, which was not appreciated as my credit card was immediately debited. This was over the Freedom Day long weekend so nothing could be done. I sent through my query. Yesterday morning I had no feedback yet, was going to follow-up which I forgot to. Later that day I was contacted by 1-Grid to assist me with my query. I do appreciate this, just awaiting my refund to my credit card now.