We have been trying to create an FBA removal order of some inventory. Below is the response we recieved after a week of trying to resolve the issue.

Hello from Amazon Selling Partner Support,

Thank you for reaching out to us. This is Prathik and it will be a pleasure to assist you today.

After reading your correspondence, I understand you have contacted us regarding to create removal order for FNSKU

I understand that this is affecting your business and I am more than happy to assist you.

Upon a thorough investigation it was found that Postal code provided is in Northern Ireland.

As per our internal investigation the information provided is correct.

Following the end of the Brexit transition period, B2B shipments greater than £135 moving between Great Britain and Northern Ireland now require customs declarations.

As a result, we are no longer able to fulfil removal orders for FBA inventory to addresses based in Northern Ireland.

As we are no longer able to process removal orders to Northern Ireland addresses, in order to have your inventory returned, you will need to:

Create a removal order with a fulfilment address in Great Britain for us to send the inventory to, and
Arrange for a carrier to collect and return the items back to you from that location.

We appreciate your cooperation and understanding in this regard.