Inefficient or Deliberate

We cancelled our Netstar contract in October 2020. In December we were told we had to pay a cancellation fee which we did. At the end of the month we were debited with a different amount and told this was the cancellation fee and promised a refund. That was December and we are still waiting despite sending the proof of payment twice. Their response - "I will escalate with finance". How long does it take to generate a refund?! Obviously they are hoping we will just go away but that ain't gonna happen!!!!!!!!