You may have seen a missed call on your phone overnight, from a number starting with the prefix +247.
This international prefix belongs to a small little island in the middle of the Atlantic called Ascension Island.
The phone will ring once, then stops. The numbers may be +247 513 437, 438, or 439. These are actually premium numbers, and will cost you a pretty penny if you get connected.
This type of scam does the rounds every now and again. Moral of the story? Just ignore it.