Person in El salvador willing to test toll free numbers

We are a telecom company and we are looking for one person in the El Salvador to test our local toll free numbers that we provide to our own customers. We are specifically from the quality control division of the company and part of our duties is to makes sure that our El Salvador toll free numbers are working and remain active, no specific skills are required. This is a simple task but we need someone to perform it from the El Salvador because these numbers are not reachable from outside the country (we are located in the US).