In my own experience CATI are more and more difficult to undertake, unless the interviewed are your current clients or have some previous relationship with you. I will rather use an electronic platform such as poolfish.

On the other hand if your sample is so limited that big platforms such as poolfish or mailchipm are not able to deliver your survey you should rethink the goal of your research remember that you can gather qualitative information with almost the same validity with a correct synthetic-analytic process