Why wasn't I able to use the first visit $10 off promo. It never worked? How does that get resolved?

When I originally joined Dog Vacay we were unsuccessful to find a sitter that could work with our time frame. So, fast forward 2 months and I again looked for a sitter for upcoming trips. When I did lock in a reservation, the system never accepted the First Time user promo code. Will that be something I can use retrospectively?