Apple earbuds volume button not working?

I have an iphone 5c by the way. I just noticed that the volume buttons on my earbuds weren't working? The sound works and everything. It worked before but now it just stopped. I had dropped my phone yesterday, a corner of the screen had popped out so I popped it back in. Does this have anything to do with it?

How to use a iphone (Sprint) in Europe for 4 months?

I'm moving to Spain to intern for 4 months, and am wondering what is the best way to stay in contact with a smartphone. I've traveled abroad before but max two weeks and depended on Wi-Fi. However, this time i know I will probably need it more for work related situations. I've been searching only and i get the sim card replacement, and unlock Iphone with the company. In my case sprint, or get a new phone abroad. I'm starting to feel overwhelmed with information.
Can I get any exact suggestions as to what to do?
It would be highly appreciated.

Iphone charger isn't working?

Iphone charger isn't working?

Added (1). my iphone7 won't charge all the way, it would charge up to 2% then it would stop charging?
like it would charge after the battery died then it would open at 2% and it would stop charging… What's going on? What should i do?
it would charge when the battery is off and once it turn on, it would stop

I brought my Iphone 7 in the hotub and stupidly submerged it and now it won't turn on. How much will it cost to fix?

While I was with a friend, I brought my Iphone 7 in the hotub with me. I fully submerged it countless times underwater thinking that nothing would happen. At first, my phone was fine, it was working perfectly. But after I let my phone die it just stopped working. I don't know if this is because the hot temperature of the water, or because the moister but I just want to know if there's any way I can fix this without having to take it to the apple store. And if it needs to be fixed how much will it cost?