missing digit of a mobile phone number

I don't know. Do you know which digit you are missing? Sometimes people lose the last digit, in which case you could try all numbers, with the first 9 you have, and then changing the last from 0, 1, 2 etc up to 9. The other thing is, to find out if there is a double digit in there somewhere. We have a number with 3 digits the same in a row, but ppl write down 2 of them, and wonder why it is incorrect. Good luck.