Here is the complaint on your forums
Having just spent 90 minutes on the phone to T-mobile customer service about why my mobile broadband keeps getting cut off I have had the following answer repeatedly.
1. It is not unlimited. I am redirected to a booster page where I get to "buy" a free 250Mb add on and CAN ONLY DO THIS ONCE.
2. There was apparently a notification of this change but I never received it. I also made a choice of mobile phone contract for my phone based on there being unlimited email and web at home. This turned out to be factually incorrect (see point 1)
3. There is a fault with the proxy page that allows you to buy the free booster or paid for boosters. The page often doesn't appear and you are without internet. THIS IS NOT ACCEPTABLE AND IS A WASTE OF MY TIME
4. Separately to the discussion about the phone contract I also within the last 3 weeks had a discussion about my email not working from my laptop on mobile broadband and everything else was fine. We had a discussion about the unlimited email and web then and it was confirmed the I still had it. No pending change was mentioned.
For anyone who would like reminded about the terms and conditions, here they are
T-mobile customer help:
See the section "Everything you need to know about tethering and mobile broadband"
Click "Fair use policy"
The fair use policy in the section "everything you need to know about tethering and mobile broadband" is here
"T-Mobile is still the only operator offering unlimited browsing and emailing, and not automatically charging expensive run-on rates after reaching your Fair Use Policy."
"Even after you have reached your Fair Use Policy, you’ll still be able to use your Mobile Broadband for text and image based browsing and emailing. So you can still browse websites, log in to Facebook, check your Hotmail or view the news on the BBC - and we won’t charge you any extra."
This contradicts the 250Mb free only.
Nothing in the above refers specifically to mobile broadband or tethering.
I am absolutely fine about youtube being blocked. I am NOT HAPPY AT ALL about an "unlimited" service meaning 250Mb free extension once a month only and it taking 20 minutes to bring up the page to buy a booster paid or otherwise.
Complaint being drafted to ofcom.