I want to change contact number

Hello, I have an activation date for my DSL internet scheduled for the 22.04 but I realized that my contact number was written wrong. The number itself its ok, but the prefix (or country code) 49 from Germany its written twice, like this: +49(0)49-17XXXXXXX I can’t change the number neither in the app and in the online portal. I don’t know if it’s relevant, because the number itself is ok, but I don’t want that the technician misunderstands my number.