How to unblock the caller phone number?

Or: **how to stop forwarding calls from given phone number?** ## Current state I have two phones, A and B. From A phone I can call whoever I want. From B I can call whoever I want except A -- when I call A, the call is forwarded automatically to voicemail. It is not about network range, or something, or not enough money. It is most likely B phone number is blacklisted on phone A and such call is blocked (forwarded). How to unblock it? ## And what happened I suspect that some call blocking app made that mess -- to test it, I actually block phone number A on phone B, and made a call. With the exactly same results as described above. After that, I removed that phone number, than I uninstalled entire application, I rebooted phone, I checked the system settings (stock blocking: off, blacklist: empty). There is no other blocking app installed (just in case I removed related calling apps, like Skype). Yet, once blocked, the phone number remains blocked. How to undo this? *Phone A (the one with such permanent block) is Galaxy Ace 2, Android 2.3.* ## Updates **Update 1:** On phone A in logs I can see all those "unreachable" calls. So they are received. Also there is small tooltip on phone A "forward call" (when call is received).