The answer is; very often you can’t. If you decide to move, you will need all new customer service numbers as well. Pretty much like a supplier lock-in. No problems on the horizon as long as you’re happy. But when things change and you need to make a switch, it will be hard. Especially if you’re active in a lot of different countries and/or have a lot of different brands each with their own numbers. Having to change them all is quite a hassle. To say the least.