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Im guessing you have an iPhone on At&t... I believe you would have to call up AT&T. Im not aware of any way you can do that from your device. Airplane mode turns off all contact, except for maybe wifi, I'm not sure. Call up your provider..
 
I think iBlacklist can do this, not sure though.
Its a free trial package in Cydia and you can opt to buy later for more functionality.
 
From reading the description, they have a blacklist and a whitelist.

For whitelist, the app will block all calls except what's on the whitelist.

You could just add your number to the whitelist and therefore it should block all other calls, maybe..
 
From reading the description, they have a blacklist and a whitelist.

For whitelist, the app will block all calls except what's on the whitelist.

You could just add your number to the whitelist and therefore it should block all other calls, maybe..

Yep the whitelist function does this just fine.
 
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