What can we do when our license plate has been wrongly confiscated by an officer out of state?

My husband and I just moved to Maryland from Indiana. We have a Blazer and a Volvo, have 60 days to register them here but plan on selling them before that because they are old and won’t pass inspection. We are looking for a new car now. Anyway last week, my husband got pulled over when an officer ran our Volvo's plates. We got 2 tickets: one for having the wrong plate on the car, another for having expired registration. Both incorrect: our registration shows that the plates are valid and belong to the correct vehicles. We called the DMV in Indy and they confirmed our plates are correct and registration is up to date. Officer insisted this was wrong and threatened to arrest us so we switched the plates when we got home anyway out of fear. The next week he pulls me over in our other car, the Blazer, which now has the Volvo's plates on it and says it has the wrong plates! Then why did he tell us to switch them in the first place? He proceeds to confiscate the plates and tow the car. We never would have switched them if he didn't tell us to, and feel like we have been set up. Now the station is refusing to give us our plates back even though we showed them out proof of registration and the original ticket. We feel like we are being screwed for doing nothing wrong in the first place, are being treated like trash and no one will listen. What can we do besides wait for a court date without use of our cars? We just started new jobs and now have no transportation.