I'm afraid that blocking both messages and calls from a specific number isn't an available feature in the Xperia C5 Ultra. You can, however, choose to send all calls from a specific contact directly to your voicemail.
From your Home screen, tap the Application screen icon.
Find and tapContacts.
Tap the contact that you want to forward to voicemail, then tap the Edit contact icon (icon with a contact and a pen).
Tap the menu button (three vertical dots), then mark theAll calls to voicemail checkbox.
TapDone / SAVE.
Let me know if you have any further questions about this!
- Official Sony Xperia Support Staff
If you're new to our forums make sure that you have read our Discussion guidelines. If you want to get in touch with the local support team for your country please visit our contact page.
I can't find blocking specific contacts and messeges
To block unwilling incoming calls and message as i know you can in most Xperia's smartphones only with 3rd parties applications like: Kaspersky Mobile Antivirus & AppLock, AVG Protection for Xperia™ which actually is installed beforehand (in variant market software package can be different, but how i saw in youtube reviews of Xperia C5 Ultra (Dual) in most smartphones was AVG for Xperia already installed, this app is 180 days PRO (free and with ads (after latest update of this app)) for ONLY Xperia owners) or many others which you can find in Google Play I used and using only these two. Both working very well, except AVG for Xperia have briliant feature to add text which will be send to author of message which you want to block. So you can write what you want and in this way to inform sender about block