Ofcom's advice on your next step

The Internet -
Customer service and Quality service

If you are having problems with migration authorisation code (MAC)

In order to switch your broadband service between DSL based service providers, you will require a Migrations Authorisation Code (‘MAC’) and your new gaining supplier will advise if one is required. A MAC is a unique code that you must obtain from your existing broadband service provider and then give to the broadband service provider you want to switch to. This allows the service to be transferred seamlessly and with little or no disruption of service.

The MAC process was developed by the industry for DSL broadband-only migrations. One advantage of the MAC process is that it protects against slamming, which is where a customer is switched to another provider without his express knowledge and/or consent.

Broadband providers have a mandatory obligation to supply consumers with a MAC upon request and free of charge.

If you are having problems switching between ISPs because of problems obtaining a MAC from your existing supplier, please see http://www.ofcom.org.uk/complain/internet/switching/