[bitfolk] does bitfolk block smtp from t-mobile ip addresses?

Hi all, T-mobile are being quite insistent that the problems I have sending emails with 4 different providers to port 587 whilst on 3G are not at their end. I believe I already know the answer to this, but can someone from bitfolk please confirm that you don't block traffic from t-mobile 3G ip addresses on port 587...? (Has anyone come across this issue before? Seems like they have some weird filtering that drops the smtp connection after the STARTTLS - even happens on other port numbers) Thanks Joseph