Strange behavior from iPhone 5

I've had my iPhone 5 for 2 years but now it's acting very weird. Several important phone numbers stored on the phones' Contacts list have mysteriously disappeared. I figured I had too many stored numbers so I attempted to delete several numbers which I no longer need, but the stored numbers I selected to delete remain on the phone! Very weird. My phone indicates that I have reached the limit of storage so I have attempted to delete some data, but that doesn't help. The phone no longer takes any photos as there is no free storage available. When using my Apps, the data switches back to Home Screen. Re-booting does not solve anything and nothing will delete. It's like frozen in time. It's the 16 GB model. My next phone will allow for micro SD cards; hopefully that will solve any future problems. Sadly, Apple does not allow anyway to increase data storage.

---

› See More: Strange behavior from iPhone 5

When you delete something are you then syncing it with the cloud and/or your computer?