Hi ZoyaM, in this case I would advise running a software update as it sounds like there is a bit of a firmware issue there.
How to use update service on the web:
1. Before you start you have to download the PC Companion software from Download for PC - Sony Smartphones (UK)
and install it on your PC.
2. Once installed on your PC, double-click the PC Companion icon on your desktop to start the update.
Note! For some models you will be prompted to do a backup prior to the update and then restore.
3. Install and open PC Companion then select Support Zone.
4. Phone Software Update.
6. Repair Phone
8. Accept data removal
10. Wait for prepare
11. Select Phone
12. Follow the connectionn steps
Please note that you will need to back up all data before using the Update Service, save your music/photos/videos to a memory stick or your PC, all phone contacts (phone numbers) should be saved to your SIM card or Memory Stick.
- When using PC Companion to update your phone, make sure you have a stable Internet connection and any Security Software ( as it might block the connection ) is disabled temporarily while using it.