Misleading customer service

I was transitioning off my parents' family plan and doing price comparison with Sprint, Verizon and AT&T. Two Sprint employees told me that I would receive a 24% discount on my monthly bill for being an employee of the local public school district, including an assistant manager at my local store. The assistant manager sold me my new plan and told me he gave me the discount. Three days later, I received an email stating that I won't be added to the discount program because my employer doesn't have a contract for the plan I chose (which it actually does). Five phone calls later, I have been told the discount is NEVER more than 15%, have been given a discount code that didn't work and spent 45 minutes on the phone with someone who couldn't fix anything.