Recently I have been getting some odd calls from someone who only rings once and hangs up. The number always starts 00232 (+232) which is the country code for Sierra Leone. Mostly it is from one number in particular which is 0023277081745 but I have also had them from 0023276310413. I don't know anyone in Sierra Leone or neighbouring countries so there is no way I am going to call it back. This is going to be a scam.
Unfortunately I have a Windows 8 phone and as yet there are no call barring apps available so I have to put up with these repeated calls. Hopefully they will eventually give up but it is annoying.
If anyone reading this also has calls from these numbers or similar and do not know who they are, do as I do and ignore them. On no account call them back or you could be landed with a hefty bill.