Hello there, NicolaMaraldo.
The following Knowledge Base article has a few pointers in regards to troubleshooting your issue, if you'd like to look them over:
Important: Only original iPhone can be charged from a FireWire-based power source. If iPhone is connected to a computer that's turned off or is in sleep or standby mode, the battery may drain.
- Verify that the outlet being used is working.
- Try another USB power adapter if available.
- If no other USB power adapter is available, try connecting to a high-power USB 2.0 port (not a keyboard). The computer must be turned on and not in sleep or standby mode.
- Try another USB cable if available.
- Also refer to iPhone and iPod touch: Charging the battery.
If you would still like to contact an Apple Authorized Service Provider go to the following link and choose your country to locate one near you:
Thanks for reaching out to Apple Support Communities.