Syarat dan terma (Term & Condition)

Last few day, my house mate told me that his phone bill increased a few hundred this month. It is due to his so call 'phone family plan' has change to limit the call to certain level. What i want to share is not talking in phone for so long nether about phone line provider but it was made known to the user.
In the case, my house mate insists that he was not let known that the term (time of free usage) has been change. In fact, all his so call 'phone family plan' doesn't know regarding this matter. When the provider was asked, they mention that they already inform all their user by mean of sms and noted in bills. It is mention in the last bill received, however it was in small size which i'm sure only a few people, if there anybody will noticed and read it.
This 'term and condition' thing already been in the system for a long time. All the t&c will be written in a small size and all the t&c (usually more than 20) will be printed in one sheet.
How are we supposed to know or noticed all the small size t&c? And why are we signed the letter and acknowledgement without really know the t&c? Who are to be blame when changes of this t&c happen? as there already one condition mentioning that any changes can be done by the provider? And the provider is not the only company doing this. What can we do to avoid/prevent this? So it still in my mind..... What in yours?