software issue

I am wondering if there is a way to "go back" to original software on the phone? I have had so many more issues since updating
Tia

I just replaced my old Nokia cell phone with a new Samsung phone about two months ago. I loved the voice quality and reliability of my old Nokia, but they don't make them anymore, so I settled for a Samsung with a small keyboard. I use TMobile and in general have been OK with their service, etc... The new phone is only two and a half months old. Intermittently I have been having connect issues. I can hear the party I have just connected to, but they can't hear me. Today almost 60% of my calls are doing this. Took it to TMobile and they are getting me a replacement tomorrow. My question is, without changing or downloading new software to my phone, how can it suddenly get much much worse ? Lastly, TMobile said about 10% of these phones in this model line do this. This is the experience of the Tech that I spoke with today.

Has anyone here had the same thing happen to them ? If you have are there any workarounds you found that help. I was told to switch to speaker phone on connect to see if that would overcome the glitch.

Finally, we don't have to worry about hackers or terrorists disrupting our communications grid or devices. It seems that the cell manufacturers already have that angle covered.