I can't send pictures on my SG4?

I have a Samsung Galaxy S4 on At&t and I'm having trouble sending MMS. I had a third party app chompsms and I changed my access points so I could send pictures with that app. I deleted the app and I couldn't send pictures from then on. I was also told if I had Imessage with the iPhone and I switched phones I wouldn't be able to send MMS unless I deleted my number from my apple account. I deleted my number but i still couldn't send MMS. Does anyone know what I can do?

My currents access points are
Name: Att lte
APN: Pta
Mmsc: http://mmsc.mobile.att.net
MMS proxy: proxy.mobile.att.net
MMS port: 80
MCC: 310
MNC 410
Authentication type: none
APN type: default, mms, supl, hipri

How often does Verizon change the terms of its contract?

I currently have a Samsung GS3 after choosing it over the iPhone 4S, and I deeply regret my decision. My 14-day return period is over, and I'm now stuck in a 2 year contract with a phone that I don't even want. My entire family (cousins, aunts, uncles, mother) all have iPhones and they love them, and I originally wanted an iPhone after ditching my Samsung Stratosphere, but I was stupid enough to go for another Samsung phone. I understand that if, on my monthly bill, Verizon changes its terms, I have a 2 week period to cancel my contract without paying an early termination fee. How often does Verizon change its terms? I really want the iPhone and don't want the GS3, but I don't want to make my mother pay the insane ETF.

Added (1). Also, don't criticize the fact that I prefer the iPhone if you're a Samsung fan.

Added (2). @Viktor, I didn't ask for that type of answer. Can you please answer my question?

Will iTunes lose all of my songs if I sync my iPhone?

So recently my old laptop died and it can't be fixed without losing all my data, which isn't backed up. This is an issue because my I had alot of songs on iTunes on there. I now have a new laptop and I have downloaded iTunes and it recognizes my iPhone but I'm scared of syncing my iPhone with new songs because I don't know whether it will delete all of my songs that are on me iPhone but not on my computer. It would take a long time to redownload all the songs that aren't on my new computer.

How does the Apple warrant replacement with an iPhone 5 work?

The lock button on my iPhone 5 is not working properly. Most of the time, the phone doesn't recognize when I press the button.

I plan on contacting apple to have the phone replaced under warranty.

Do they send me a replacement phone first, then I send them the defect?

I'm in the middle of a move, so I do not want to be without a phone, if avoidable.

Why does my iPhone keep overheating?

My iphone 4 keeps saying that it needs to cool down yet its not even hot.It'll work for about 5 minutes then go back to the temparure screen. Turning it off and on helps but only for about 5 minutes.

Is having two screen protectors on my iPhone a bad idea?

I'm getting my iPhone 5 soon and I have two Otterboxes ordered: defender and commuter.

I want to put the adhesive screen protector on that comes with the commuter series anyway, but if I put the defender series case on, will the two screen protectors cause a problem together (bubbles, rainbow)?

In a situation where I have no case, I want to have the screen protector on.