Changing an ecommerce merchant number (MID) with Sage Pay
If you have an ecommerce site with Citrus-Lime, and accept credit card payments on the site, then you will have an account with Sage Pay, the payment processor with whom we integrate.
In simple terms, Sage Pay is the intermediary between the financial institutions involved in a card transaction.
When your Sage Pay account was set up, you would have provided them with an ecommerce merchant number (MID), which in turn you would have received from your acquirer. Some example acquirers are Paymentsense, Worldpay, and Elavon. Acquirers are responsible for collecting and moving your customer's payments into your bank account.
Sage Pay's role in this part of the process is advising your acquirer about the transactions that have taken place on your ecommerce site, and therefore what payments need to be taken and from which customers.
You may decide that you wish to change your acquirer, perhaps to another acquirer who can offer you better rates. If you take this course of action, your new acquirer will need to issue you with a new ecommerce MID.
It is essential that you then let Sage Pay know that you wish to change the ecommerce MID in use in your Sage Pay account. Failure to do this could lead to credit card transactions failing to process on your website.
To change your ecommerce MID, you will need to complete the form located on this page: https://www.sagepay.co.uk/merchant-number-change-form and submit this directly to Sage Pay: firstname.lastname@example.org
With regards to this, it is worthwhile reading the notes on this page to make sure the submission is made correctly: https://www.sagepay.co.uk/support/12/38/changing-your-merchant-number
Note that the ecommerce merchant number change request form MUST be sent from the listed billing contact email address which is associated with your Sage Pay account. Sage Pay will reject the form if it is sent from any other address.
You do not need to advise Citrus-Lime if you change your ecommerce MID, as this has no impact on how your website integrates with your Sage Pay account.