My B Key Isn't Playing

Hi so I bought a very cheap children's accordion for myself to see if it would be something worth pursuing. I bought a D 'luca kids piano accordion. I LOVE IT! Great considering the price! The only problem is the B key won't play when I push my left hand in. Most of the time it works when I pull my left hand out but it's not consistent. It sounds airie like air is escaping from somewhere when I try to play it. I've only had it for a day so I can send it back but does anyone know if I can fix it myself? I know people are gonna say that you pay for what you get but all the other keys work perfectly and I can't afford a real one right now. Thanks for the help I appreciate it:)