Client of T-mobile having an iPhone 4 & iOS 7.1.2 - problem with connecting to the Poland's network

Hello, it's just a question fot the client of T-Mobile having an iPhone 4 with the 7.1.2 firmware installed.

When I did the upgrade I lost my internet. Impossible to get it back. I didn't go to the shop yet. Does anybody had the same problem when upgraded?

When I try to put internet back on the T-Mobile website I have this message : Aktywny APN (T-Mobile Internet lub T-Mobile WAP) wymaga aktywnej usługi Dane asynchroniczne 9600bps

I didn't find anthing on internet so may be it's a problem with my phone only or only between T-Mobile Polska and iOS 7.1.2

I never had an iPhone nor I ever will.
The problem you are having is as follows, during update your APN was erased.
Newer devices might not to be up to speed with the mobile provider(s) or vice versa,
plus devices like the iPhone only have a limited number of these carriers built in (usually the carriers which have an official relationship with Apple)

For example T-Mobile in US just recently started selling iPhone.. so in older iPhone devices T-Mobile network wasn't listed in APN.
APN=Access Point Name
BTW, is your iPhone jailbroken?

APN principle applies not only to iPhone but Android and other OS's

From what I understand T-Mobile in Poland is not that long---I judge this from conversation with my friend from Poland who never heard of T-Mobile before, about 2 years ago.

First get in touch with T-Mobile rep in Poland and see what he/she has to say.

Solution # 1 revert to previous OS version (i think there is a time limit that you can do so)
How to link : daily.bhaskar.com/article/GAD-unhappy-with-ios-7-here-is-how-to-downgrade-to-ios6-4380650-NOR.html

Solution #2a go to PDA/Smarthphone Forums and dig for answers. Do not settle for anything less then this following Forums. I give you a link to the similar thread for starters.

Do not pay attention about different devices, principle for APN is the same.. just Apple is messing things up.
link: forum.xda-developers.com/showthread.php?t=2586058

Solution #2b go to iPhone Forum, regarded one of the top ones for Apple.
link: forums.macrumors.com/showthread.php?t=1642124&highlight=after+upgrade+lost+apn

Last but not least, use common sense, if not sure what you are doing, don't do it.
I take no responsibility whatsoever if you brick your phone. XDA Forum is for developers.
Good Luck.

Sorry, I should have closed that topic earlier. But I'm kinda very busy at work. Summer season :-(

Problem is solved. Infact someone at T-Mobile didn't follow my requests and just cut my internet contract few weeks ago. And I didn't know it because internet was still working. So they were charging me while I was surfing and while I shouldn't have.

In fact now, because of some employee who didn't do what I wanted, I have no more internet and a huge bill to pay...

It was as simple as that. Nothing wrong with the phone or the company. Just with a misunderstanding.

NB: I think T-Mobile is in Poland for over 5 years. It was ERA before, and I'm pretty sure T-Mobile bought them a long time ago.