VIVATEL prepaid sim card and roaming

[inquisitor]

Извиняваи забравих:

USSD commands all work properly. *102# returns the credit, *103# the current tariff and *104# details on promotions.

Also I've just tried to register with all other German networks manually and I was admitted to T-Mobile, too.
Yesterday I used a function called "select new network", which obviously didn't try those networks, which refused my SIM before.