Has anyone else had problems calling T-Mobile numbers from Vodafone and
experienced their own voice at full level echoing back at them when making
calls? It appears from the callers end (using Vodafone) that the call hasn't
successfully connected to the network but when the other caller answers, you
won't hear each other but your own voices each echoing back.

This seems to be a problem on various T-Mob No. ranges, certainly those
listed below (possibly all others) and can also occur where these numbers
have been ported out to other networks:

07931
07940
07944
07950
07958

Vodafone's Technical Support fobbed me off telling me it's T-Mobile's
problem but it is never an issue when, for example, someone on O2, Orange,
Three or T-Mobile themselves calls people on these number ranges.

Has anyone else experienced this problem? If so and it's annoying you as
much as it is me, I'd advice you all call T-Mobile or Voda CS and hopefully
we can get it resolved as Vodafone seem disinterested in dealing with the
issue, rather to fob me off and actually told me to ring T-Mobile myself!!