I hate my Behold II

I'm on my 2nd Samsung Behold II.  T-mobile sent me the first one when my G-1 straight up died after 6 months of owning it. Shut down, wouldn't do anything.  So they sent me this "new" phone to replace it.  After 2 weeks, it shut itself down constantly, froze up and dropped every single call... so they sent me a new one.  I've had this one about 3 months, I don't use it for much, no music, not a bunch of apps, just Gmail, Facebook, camera and Touchdown for my Exchange server at work.  Now it's constantly telling my storage memory is low and I can't receive text messages.  I've deleted almost all my gmail, my touchdown email, my call log and my text messages... still no luck.  And now it won't download Gmail.  Oh, and this one also restarts itself frequently, although not as often as the other one, but this one locks up when it's turning back on.  I was trying to hold out until my contract is up with T-Mobile in March (been with them over 10 years) and going to move to another provider because their service and their phones have really gone down hill, but I have to be able to use the phone until then.  Help.  And don't tell me to restart the phone, I've done that dozens of times.  Thanks.  Sorry for the vent, I'm very frustrated with all new "smartphones" as they never work right.