Hi @mostafaibrahi,  

The reason you can't see/change your subscription yet has to do with the fact that you still need to add it in your account. Is this about your mobile or your T-Mobile for Home subscription? You can add it by clicking on ''I still have a subscription'' or in Dutch '’ik heb nog een abonnement'’. If you click on that and enter your number, a text message will be sent to you with a verification code. Once you enter it, your subscription is in there and you can see all sorts of things and also make changes. Can you let me know if it worked out? I'd love to hear it from you! 

Kind regards, 

Pharwin