Hello,
I've got the change letter by registered mail (stamp 25 March 2009) the letter was in german language. Two or three other UM423 customers received this letter, too and reported this in various user-forums (e.g.
Telefon-Treff - die Mobilfunk-Community in german language --> Prepaid --> "Der United-Mobile Thread")
I talked to UM this Morning:
The UM423 System is still "broken", what means, nobody can make outgoing calls or send outgoing Text-SMS at the moment. What works are incoming calls and DATA (tested by myself)
I cannot be said, when the UM423 will be complete ok, but they are working for a solution.
The UM-Customer Care suffers under a big lot of requests for transferring money from the UM423 to the UM+ account, so they ask for a little patience.
I'll come back, if there are additional news from UM.