T-Mobile and Trustworthiness

Have you ever got annoyed by those services that you initially thought were so "trust-worthy" when you had decided to go for?
I have been a customer of T-Mobile for almost 7 years and T-Mobile is named as the best network service in all kinds. Infact, T Mobile is good for business customers. Even though a bit more expensive compared to most other networks, they provide good services and you get no trouble at all. I've had no problems with the coverage as well. Almost everything is perfect and neat! Everyone in my family is with them.

However, today I was forced to argue with them. And I still can't believe it. The finalised bill of last month came for 100 quids (£100, rounded up). I was shocked! (You should make a note here that my line rental is only £25). And I have never used minutes or texts outside my allowance before and nor did I in last month. But the bill exceeded to a high number. I wouldn't worry about it for a single sec if I had for god sake used extra mins. Putting this in perspective I would say fine, its my fault.

But this happened because of the fault of the previous officer to whom I talked about updating my contract. It was then when things got messed up. He agreed with the date that I asked him to update my contract on. I enquired him about all the extra charges I would have to pay and it was all agreed. The last thing I asked before disconnecting the line was that he makes sure that the system changes my contract on that specific date I wanted (which is my billing date). He assured yes, all fine, I was still on my old contract till the following billing date.
But that was not true. What he did was that(although they now claim that the "system" changed it) he changed my contract immediately on the very day I had talked him to. They charged me for the mins that I had used during last month, neglecting the previous contract mins allowance but as if I was on the new one (with less mins allowance than the previous). Confusing but it makes sense to them!! Complicated but intelligent system they've got you see!! *Sighs* They blame their "system" at the end of the day for every question that they fail to answer.

After a while of explanations and arguments.......They said they were giving me 5 free international texts as a compensation, "to make me happy". Five international texts would cost me only a pound. So that should say, a pound is their max. compensation option for the money I have been charged for nothing. Whatta customer service!! I am now thinking if I should switch to a different network.(though my dad will surely oppose this as he is with them for about 10 years).
I could have figured out this fault if I logged on to my account online to double check that they didn't change it on that day instance but I didn't get the time to. But there should be no needs to chase them and check if they are doing their job properly. Why do we have to? A company is trusted only when the customers can sit back and relax without double checking or triple checking that they are doing what we asked for.

Ensure that your dealers are doing their job properly. Give some time on that. Because of today's world, if you don't do this additional service for yourself you will be fooled for paying money, I would say.
As a consumer, these days it has become your responsibility to chase the companies/marketer to ensure that they don't forget/ignore to do what they are supposed to for the payment you would have committed. Except debiting your account, which automatically happens ON TIME. Poor businessmen, they are trained enough only to butterup the customers to make them commit to their services but not enough to be more clear and specific when they talk at their customer services dept. So people, its utterly your own accountability to take care of the worthiness you expect for the earnings you turn towards consumer products. Forewarned.