T-Mobile has quite a scam going.

I took my new Nokia N95 with me to Turkey last month and played with the GPS and Google Maps quite a bit, and did the occasional browsing and twitter posting as well. Using maps on a phone chews up a lot of data since it constantly downloads images, so I made sure to only use it from WiFi spots at my in-laws’ or friends’ houses. I wasn’t worried about accidentally downloading the images from a local phone network on 3G or GPRS since I never set up a local access point, and anyway I have my phone set to always prompt me to choose the data connection to use.

I was very pleased with my phone, bragging that WiFi and GPS were a surprisingly useful bell and whistle when used in combination abroad.

I got the phone bill yesterday. £50 in roaming data charges.

Apparently, T-Mobile tracks how much data you transfer over wifi, and bills you for it. Never mind that you are transferring data over your own network connection, nothing to do with T-Mobile other than having bought the phone from them.

Now I’m scared to use my phone. What if I agree a business deal over my t-mobile phone, will T-Mobile deduct a commission from my phone bill? I once negotiated a raise over my mobile, do I owe T-Mobile a percentage of my salary every month? Forever?

I found a forum post from someone who made the same discovery. I’m sure it’s embedded in the Terms and Conditions.

I’ve been a T-Mobile customer for 10 years. Unfortunately, it’s 16 months until I can freely switch. But I will.