Contract Review for Cancellation Dispute

I need a legal professional to review my ADT contract. I want to validate my cancellation request.

Key focus areas:
- Cancellation terms
- Timing of business days (Is Saturday a legal business day?)

I signed the contract on Wednesday, 7/15 after 4 PM. According to the "3-Business-Day Cancellation" clause, my cancellation should have been valid on Monday, 7/20. However, my request was denied.

Ideal skills and experience:
- Familiarity with contract law
- Experience with cancellation clauses
- Knowledge of business day definitions