Yes it is quite bad isn't it. Especially considering you have to put money into the account before you can use the modem, then if you go over the 3gb per month they cut you off, but it is the most liberal of the lot of the providers. Vodafone do their 'unlimited' product which is 120MB a MONTH
Three do their 1GB a month
and whoever is left, well they're not worth considering as they either don't have priority on their chosen networks or don't offer a compatible product.
My own usage pattern is going to periodic ie: use it for a couple of weeks here, maybe not use it for 2 months then use it again. If I were you I would have gone like yourself for the same £30 a month package, but that's only as my msn addicted mate uses the same service all the time and says he has no problems and gets full access to the internet as opposed to the 'walled garden' that Three used to offer, though they now allow access to all the internet apparantly, but still 1GB for a MONTH... They need to revise that I think.
Having re-read your original post, I should appologise as none of this helps you in trying to solve your msn dropping connections when using t-mobiles service. My mate uses trillian
http://www.ceruleanstudios.com/ to keep in contact with his friends on various chat clients he advises. Or there's the t-mobile
http://support.t-mobile.com/knowbase...ic/tm22923.htm which could offer a solution?