IIRC you can move from TK to others freely, but if you move to some options there are conditions to come back. TK service via email, phone, etc is amazing, eve

IIRC you can move from TK to others freely, but if you move to some options there are conditions to come back. TK service via email, phone, etc is amazing, even if your German is not very good, as it was the case for me the first year.