We tried to register our brand on amazon.co.uk, however received negative decision.

Here's message from Amazon:

We are unable to approve your Brand Registry application because the trademark on the application either violates the intellectual property rights of others and/or is highly likely to be confused by customers for an established brand.

We are the official registered owner of the trademark in the United Kingdom, registered with the UK Intellectual Property Office under registration number since year 2000.

Despite trying to escalate we're receiving exactly same answer from Amazon without any intention to consider our situation. On top of that we see many sellers selling products with our brand on it which makes us impossible to have any impact on how our brand is represented on Amazon after they deny possibility to register as brand.

Any suggestions what to do?