stroller dilemma

So my mom bought the travel system we wanted off of our registry so we get 15% back and a year of returns. My MIL just told me she got it already but didn't get it though the registry. We will most likely be returning that one because we don't have long to return it and we didn't get the 15% back from babies r us. She always told me "wait until someone buys it off of your registry" and she doesn't even buy it off the registry so now she's buying a double of something. I appreciate it, I really do but this is what a registry is for.