BlackBerry 7750

I am new to this website, but I need help. I just got this Blackberry 7750 from a friend that had it from his business. His business had blocked the ability to send text messages because they obviously want their employees to work, not play. On the other hand, I only text message and wanted this phone for the keyboard. I recieve text messages but cannot respond. I do not have the option. The company must have erased the option or program from my phone. Does anyone have any suggestions???