On top of the "Betamax problem", I just noticed that the forwarded Budgetphone numbers can't be reached using the PSTN format.
But if I use the SIP-broker format, the connection can be established.
So, is there a Betamax related problem at all, or is something terribly wrong with the Voxalot servers, not accepting "alien connections"?
Edit:
I just changed on my Voxalot account page, the preferred cluster from eu.voxalot to us.voxalot and my forwarded Budghetphone number can be reached again