Jim wants to call his friend Bob. Bob's Phone number is 976-6419. Jim dialed this number perfectly but then ended up calling the wrong house. He tried again and dialed the number perfectly. Once again his call didn't go through, in fact his call never went through to Bob.
Why couldn't Jim call Bob?
Alan's tip gave me an idea; on the phone, each number can also represent some letters:
9 - WXYZ
7 - PQRS
6 - MNO
6 - MNO
4 - GHI
1 - (no letters)
9 - WXYZ
Using these, the first five digits of the phone number could spell WRONG... thus, he dialled WRONG-19 or WRONG-1X or something.
I don't know how that might relate to an answer though. Some possibilities:
1) In whatever country Bob (or indeed Alan) is from, there's a directory service for wrong numbers which starts out with WRONG.
2) Jim's friend is Bob Wrong, and the "wrong house" is actually Bob's house.
3) There is another family named Wrong who vainly chose their phone number to reflect that fact.
Unfortunately, none of these strike me as an obvious answer. Hopefully someone can use this posting to come up with something which closer approximates the solution.