Here are a few suggestions:
1. Read through this webpage and follow the appropriate steps.
(If you cannot use iTunes or the Cloud to recover, you will need to use the third process called Recovery Mode)
If using recovery Mode, here is some further material to review:
Video documenting process and another
step-by-step guide
Note: Recovery Mode will of course wipe the phones content.
2. If all the above fails, there is "apparently" a program called
iPhone Care Pro program that has a passcode unlocker. I have never used this before and cannot verify it's feature. If all else fails..it's maybe worth a try.
3. Some links and guides on Apple Support Site:
How To Remove Password From iPhone 5. I forget my password!!!
I hope you come right.