Living in company towns made it difficult for workers to join unions in what way

In company towns, most services (housing, education, etc.) were provided by the employer for the workers. This meant that the workers depended on the company for the fulfillment of all their basic needs.

If the company disliked the idea of the workers joining a union, as they often did, then they had several means to pressure workers into compliance. They could raise rents or evict them from their homes, for example. This monopoly put workers in a tough situation, and discouraged them from joining unions.