Why do my contacts keep deleting/disappearing?

Lately on my iphone 5c, my contacts have been disappearing. I looked in my contacts one day and realized that a lot of them have been deleted off the list. Every time I try to fix it (like click on them in my messages and click create new contact), a minute or so later the caller id disappears again! And I've tried looking up information about icloud and stuff since I thought maybe it had something to do with icloud, but I'm not sure. And at first, I thought I'd figured out a pattern, like it was only deleting those who had iMessage. But no bcuz even some of my friends or family that I know have androids have been deleted from my contacts list. And then I'll look through my messages and our conversations will still be there, it's just that there's no caller id. ITS Really ANNOYING! And it's like it can only hold room enough for one more contact, bcuz I tried adding my boyfriend and he actually stayed, but then I tried adding my brother too and right after i saved him in my contacts, it replaced my boyfriend (or so it seemed, cuz then my brother stayed in the contacts.) I also thought maybe it had something to do with my contacts being synced to Facebook? Bcuz that's another thing: one day I noticed that I had a lot more contacts added to my original ones, and soon found out that my fb contacts have been added to my phone, even though I don't remember ever syncing them. So I turned fb contact syncing off but it didn't solve anything at all, I can't save my contacts period.

Car subwoofer and amp combination?

I was wondering if this sub amp and head unit will work well together also which wiring cable would I need to use

Sub http://www.caraudiodiscount.com/w3001d4-inch-subwoofer-ja690-amplifier-box-p-12811.html

Head unit http://www.caraudiodirect.co.uk/pioneer-deh-2600ui-car-cd-usb-ipod-iphone-android-tuner

Wires
http://www.caraudiodirect.co.uk/accessories?cat=8

I'm unsure if I need a 2000 or 3000 watt wire package

Also which connector would I need to connect the head unit to the car I have a seat ibiza 2006

EBay starting selling advice?

I'm thinking of selling on ebay, I managed to get hold of 100 iPhone 6 cases at a silly price to see how it goes,

Can anyone give me and selling tips and advice where to look for products and what to sell?

Stuck iPhone 4 lock button! Stuck/Stripped screws

Okay so, I've had this stupid panda case on my phone and it jammed my lock button. It still works if you push super hard from the side, but no clicking sound. I saw how to fix it by opening my phone up but the screws won't come out no matter what! I tried a screwdriver alone, with duct tape, rubber band, double sided tape, everything! I don't have a warranty on my phone, and I'm looking for a super inexpensive (>$5) way to fix it, any ideas?

Why won't iOS 8 install on my iPhone 4s?

Been trying to install the update all week and it keeps getting to almost 100% installed and downloaded and then it says it can't install IOS 8. I can't find a reason as to why it won't install, any advice?

How to get music off my laptop to my iPhone?

I've downloaded music from Tumblr onto iTunes on my laptop, just where it says 'songs'. I've tried connecting my phone then syncing it but nothing shows up different on my phone. How do i put it onto my phone?