For UK customers, you could do bank transfers, to your personal a/c or to your a/c with a crypto exchange e.g. Kraken. Not a great solution as it doesn't help with for non-UK customers and allow card pymts which most UK & non-UK people want/expect. But it may keep some funds coming in, while you transition.

Perhaps setting up a new company with a generic name like Internet Educational Services and detailing that your courses are internet focused learning courses without ever mentioning crypto. This may not draw the attention of bank compliance systems. However this presupposes your business name and company details mention crypto. I assume this is how it was flagged to a bank compliance system.

However, bank compliance staff maybe searching the web to see if the business is as described on public company records. I doubt it though, as having staff individually search the large amount of small businesses would be an extensive task. I imagine this is an automated process tied to XBRL data, freely available, from the companies office. Someone can correct me on this, if I have it wrong.

Once you have the new company setup, then apply to the usual card processors for pymt receipts.

Banking redundacy, might be called for though. Perhaps a more crypto friendly country will allow you setup a business and bank account, Isle of Man, Cyprus, etc.