Unlcoked iphone from 02 to vodaphone, can i switch back?

I used to be on o2 on my iphone but didn't want to no longer, so i swapped sims and it wouldnt work so i got it unlocked. Now i have this new sim in i've had it for a while now, i'm thinking of possibly swapping back, will it lock to my o2 sim after so i can't change without paying again?

I need to unlock my locked iPhone 4 on o2?

I bought an iPhone 4 when I was back in England which I was told was factory unlocked but it had cydia jailbreak so I deleted it and didn't pay much attention to the problem. But I had the phone for 2 years and software is old and needs update so I took it to a local phone shop ( now am in Libya my hometown ) and I provided imei and was told it was locked to o2. I wasn't givin the original o2 sim that came with the phone. Can the phone be factory unlocked if I gave it to a family friend who is going to England for work and is it an easy process because I don't won't to stress him out as he isn't gonna have much time and paciance. Should I give him my iPhone to get it unlocked?

Some songs won't sync on my iphone 5?

I bought some albums from FYE and the Gandhi Cafe, and imported them to itunes,
and when i click on sync, they won't show up on my iphone.

how can i fix this?

My iphone 3gs won't activate?

I had just updated a jailbroken(probably) and unlocked iphone 3gs to IOS 4.1 to 6.0.1. After the update, it won't activate. Any help would be great. I hope this can be fixed. Thanks.

Added (1). When I try to activate it trough iTunes, it says, " We could not activate your iPhone at the moment etc. " and when i use Wi-Fi, it says, " Your iPhone can't be activated because the activation server is temporarily unavailable." I also got a SIM card that I used to use at the Philippines, but now I have migrated to Canada, which makes the SIM unusable.

I can't use my iphone after software update what do I do?

So my phone told me to update the software and so I did. But after updating, my phone wouldn't turn on, the only thing that showed up was the screen that's telling me to connect to itunes, and I did, but it stayed on that screen and itunes said I can't use it unless I restore the backups. The backups were stored in another computer which is broken, and I can't restore with my itouch backup, and I have no clue what to do because my phone won't turn on at all nor are the back-up keys showing…