Strange...
How does the gear get stuck up in a PA34?! Slow to below 85kts and pull the red knob. The gear in a Seneca is held up by hydraulic pressure, with an electrically operated pump. Pulling the knob relieves pressure and allows it to fall free.
Still, good result that no body got hurt and the plane looks like it can be returned to service. The PA34 has skid rails along the underside just for that purpose, so it should come good with a little work.