Based on your description, there are at least three entities, first state clearly the what's of these entities based on the user requirements, e.g.:
1. What is a company, its purpose, and its data attributes?
2. What is a contact, its purpose, and its data attributes?
3. What is a rep, its purpose, and its data attributes?
4. What is the relationships between them, if any?
Use a diagram to represent points 1 to 4.
Use this as reference
Introduction to database design[
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