How many telephone numbers do you want to qualify database interesting enough? 100? 500? 1000 or more?. I ask you this question because it is not easy that any mobile company sell all of its database, but it is easier to collect several hundreds of numbers from family, friends, customers, and all of the people I could have contact with in my daily routine. I am colombian, living in Bogota. So, I thing I can do a good work for you in this project.
Which specific information do you need for each number? Name? What more else?
It is important to be confident when you contact number owner: it is better he/she won't know how you could get the number.
Final question: How much money will you pay for each valid number?