Default So...what's the skinny on CDMA/GSM S5's? I need help urgently!!!

Hey gang,

I'm not as tech savvy as I used to be. Long story short, my fiancee and I got "baited and switched" into switching to Sprint (from ATT and Tmo, respectively). As it turns out, we get NO reception almost ANYWHERE around our home. My dB is normally 105-120 at home, and I use my cell as my business phone. It's cost me a lot of money.

I've tried fruitlessly to get the devices returned, but they just soak up time and give us the run-around. I'm very close to trying to sue for breech of contract or similar, not having the services we were told we would have.

Anyway...I know Sprint is CDMA. Is this S5 a tri-band phone? In other words, can I pop a Tmo SIM into it and use it with a prepaid Tmo SIM, assuming I root and rom?

Here's the info on the model and frequencies...
http://www.gsmarena.com/samsung_galaxy_s5_cdma-6338.php

Someone please help. I'm being forced to buy a SIM from another carrier and carry around 2 phones, just so I always have one that works.

Thanks in advance.
Device :: Samsung Galaxy SIII, T-Mobile (T999), USA
Android Version :: 4.3
ROM :: .::StockMOD ROM::. | TouchWiz 4.3
Recovery :: TWRP 2.6
Kernel :: 3.0.31-1804024
Baseband :: MJ4
Build :: MJC