Watch Station Promo Code Didn't Work

On January 22nd, I purchased a smartwatch from Watch Station. So, I started using the watch and realized that water got inside, even though it was supposed to be waterproof. I got in touch with customer service right away, and they gave me the option to either fix it or get a promo code for a new buy. I chose to use the promo code to switch to a different model. But for the last two days, every time I attempt to finalize the payment for my new watch, the promo code is not being accepted. I've given it a shot several times, but it just won't work. I can't get a hold of customer service, and I've reached my limit and decided to stop trying. I will never, ever buy anything from you again.