Samsung was broke than fixed but afraid it may be broke when returned

Question

so i brought my samsung fascinate in because it would charge all night and the battery would die in an hour. it also froze on apps and would take several attempts to get a page to load or a app to load with full bars. i would have to switch data on and back off several times. i took it up to best buy. the guy said hes going to reset the phone  and said it should run good. i also asked why my phone was so hot. he said it was normal.
that night i plugged my phone in to charge and it seemed fine. the next morning i woke up and the phone was stuck on a charging screen and couldnt get it off. i pulled tyhe battery and tried to cut it back on and i got a computer symbol, mobile symobol and a triangle with a exclamation point in the middle. its broken again i thought . so i went back to best guy and the guy there couldnt figure it out so they said they are going to send it out and that it should take 3 to 5 days.( the paper said it could be a month's wait). but they had no loner phones and i have no old verizon phones being my first time with verizon. so im stuck with no phone dont really know when my phone will be back. my fear is that when it comes back that it will just crash again and i will have to go through this process again and apparently they dont make fascinates anymore so the guy said it would be another phone from samsung if they cant fixc. probalby the samsung charge. i dont like that phones. its too bulky looking. thats why i chose the fascinate its thin. cant i just pick a different phone on verizon thats the same price. very frustrating

Answer 1

Did you root the device or try to run an alternative firmware?
"i pulled tyhe battery and tried to cut it back on and i got a computer symbol, mobile symobol and a triangle with a exclamation point in the middle. "
That's Samsung download mode.  There are two possible ways to enter this:
1)  Severe hardware failure
2)  You're not telling the story and were using Odin to flash alternative "cooked" firmware
I've seen that screen before on my Samsung Infuse, but I got there through route 2)  (I work with a few other developers on maintaining third-party custom firmware for my phone - hosing your device on a regular basis is kind of common for developers.)
Actually there is a third possibility, but it's remote and unlikely:
3)  There were some Android malware apps available for a brief time that would root your phone and then do unusual things.  I've never heard of malware that would put a Samsung into "forced download mode".
It's not normal for the phone to run hot unless you're running games and such.  Phone running hot would indicate some app is in the background eating CPU cycles, possibly malware.
Unfortunately you're kind of screwed, for two reasons:
1)  Unlike AT&T and T-Mobile, you can't just throw your SIM into a backup phone since Verizon and Sprint use network technologies that don't have your account tied to a SIM, but directly to the phone itself.  If my phone dies, I can throw the SIM into an old phone that I haven't eBayed yet or a $20 goPhone unit.
2)  Samsung just did a MAJOR rollout of next-generation devices, but for some reason Verizon decided not to deploy their own variant of the Galaxy S II.  However there are rumors that the next Google Nexus device (Nexus Prime) is coming out on Verizon in 1-2 months.  There's also another Samsung device coming (the Stratosphere) but ETA is unknown - it's a Samsung with Android and a QWERTY slider keyboard.
*disclaimer* I am not now, nor have I ever been, an employee of Best Buy, Geek Squad, nor of any of their affiliate, parent, or subsidiary companies.