In my migrating servers from one provider to another, rather than to the first provider's new platform, it turned out that the first somehow missed that I had ended my services with them and thought that they were all continued into the new platform. Fortunately, they seem to have readily corrected their records, cancelled further invoices, etc. On learning that they had thus overbilled me, they assured me that a refund had been issued. After pressing them a couple of times on this refund's absence, it turned out that actually, there had been another mistake. I did get my refund in the end but, goodness, it helps confirm my decision to migrate.