How do I ensure that customer numbers are not overwritten in Visma Business?
Order bases generated by Loomis-Pay will by default use the customer ID automatically assigned to a customer after creation in Loomis-Pay . This is a running number series starting at 1. If you already have a customer register in Visma Business, this can be problematic as the IDs do not match from Loomis-Pay -> Visma Business.

How do I solve it?

The customer card in Loomis-Pay has a field called "Ref / Reference". If this field is filled in, the value filled in the field will be used as the customer ID in all export files generated by Loomis-Pay . Fill in the "Ref" field with the registered customer ID from Visma Business, so that the customers are matched correctly from Loomis-Pay -> Visma Business.