Hi AmazonNETP,
It is important to establish whether you are an established UK business or a Non Established Taxable person.
Please see the guidance below which explains this difference:between these two statuses:
Who should register for VAT (VAT Notice 700/1) 9. Non-established-taxable-persons (NETPs) — basic information
If you judge that you were a Non Established Business prior to your Registration date then there would have been a requirement for the marketplace to have accounted
for VAT on your sales .
The marketplace will be accounting for this VAT over to HMRC and so I would contact the marketplace to discuss this payment.
If you judge that you are a NETP then you would need to consider whether you would need to register for VAT or whether there would be an advantage to registering for
VAT if you are making supplies of goods which are in the UK at the point of sale.
Please see the guidance below:
VAT and overseas goods sold directly to customers in the UK Goods that are in the UK at the point of sale
If you determine that there is no requirement to register for VAT then you should look at cancelling your VAT registration and completing an error correction for the VAT which you have paid over to HMRC incorrectly since VAT registration.
Please see the guidance below:
VAT Notice 700/11: cancelling your registration
4. Correcting VAT errors on a return already submitted
Thank you.