Finding Out GMRS

Hi all, Does anyone know if it's possible to find out what GMR a declaration is on? We are having issues with hauliers constantly stating they haven't created a GMR, but when they try to add the MRN onto a GMR, it gives them the warning it's already on one. But as I'm unable to see any GMR numbers, or prove that they've already raised one, I'm having to constantly cancel and re-raise imports. Getting slightly frustrating. Thanks in advance!

Hi,
Please contact our imports and exports team for guidance on your query.
Imports and exports: general enquiries
Thank you.