(Following on from a previous entry.) After weeks and weeks of trying and failing to get a meaningful reply from the lady who was dealing with my refund, I received a bill for an outstanding amount; I knew that I still owed some money, but I wasn't sure of the actual amount.
I opened another letter which looked very similar to the bill I had just opened, only to discover that it was the refund I had been waiting for! And not only that, but it was significantly higher than I was expecting! However, after checking my bank statements I realised that I had missed a few months here and there when calculating what I was owed.
I couldn't be happier to finally have this dealt with and put behind me.