I have tried to make skype calls from my handset (n900) to my contacts that use skype and i hear them for like 4 secs undisrupted then it breaks up on both ends.

I am using t mobile for my internet and other people I know use the same without any problems. I changed my phone to see it the problem would rectify but the same thing happens
.
Everything else works fine like the messaging, its just the calls that make don't work properly