Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Hmm we need a little more info - like the software version of the phone and how you tested it before you bought it!
Also power on the voice recorder and try to record your voice off of the headset and see whether that works properly - you should do a couple of these test and establish if the mic is working properly and please do them without any cases as sometimes they are not for the specific model and obstruct the microphone.
I do not know of any problem where the microphone would not work when on headset but will work when on speaker phone.
Well this is really the next thing I would recommend - if you do not have a lot of apps or you don't mind loosing them, I would do the following.
Turn off the phone - Once it is off hold the volume up and down and press the power button until the vibration stops. Release only the power button and wait until the phone goes into the official recovery window. Factory reset/wipe option and erase the phone and bring it to factory settings. Power it on and without any apps installed (only your gmail account hooked up for your contacts) call your boys/girls and have a chat with them to see if anything changed really!! Test it for 2 days - if the problem does not occur any more install your apps one at a time testing the phone making sure it is not one of those bad boys that creates a problem.
If you still have a problem right after you factory reset - I would say go back to gingerbread and try that. ICS has brought a lot of problems which were absolutely not warranted - this is because it is old version of ICS - the latest one is 4.0.4 . There is a guide on how to install stock Gingerbread rom on your phone in the forum just one web page back. I would say if you do all of these steps and there is absolutely no improvements there has to be something wrong with the phone. At that point you may want to bring it into t-mobile and see if you can ask them to take a look at it (just tell them you got the phone from a family member so they do not become greedy all of a sudden).