VAT on Cash Receipts then Deregister

Question for any VAT experts out there

Company A registers for VAT because turnover is over the threshold BUT they also opt for payment of VAT on a Cash Receipts basis (because turnover is bleow THAT threshold)

Therefore they issue invoices to debtors as normal and return the VAT as they get paid.

No problems with this obviously

However

Then business slows down and turnover drops below VAT registration threshold so Company A decides to deregister for VAT

However they still have a number of debtors as at date of deregistration who will have already been invoiced inclusive of VAT but have not yet paid

When (If!) those debtors pay, how does Company A return the VAT to Revenue if they are deregistered and no longer have to submit VAT returns.

I would have thought that company A derigistered prematurely and will have to pay the VAT on said invoices.

I agree that the VAT must be paid but is there a mechanism by which it can be paid?

If they have to stay registered then it becomes a vicious circle as they must keep charging VAT on their sales invoices.

could you collect all the os vat money in due course and file a backdated supplementary vat 3 for last registered period

That's looking like the only option at the moment which is not ideal.

It'll be next to near impossible to wait until it's all collected without spending at least some of it!