Every shady landlord withholds the security deposit, often with a side order of running up repair bills.

Their MO is always the same... completely ignore you until and unless there is a threat of legal action. The options others have come up with are basically the 'triggers' that could trigger a replevin (look it up).

Certified demand letter: cheap, might be 'legal' enough to get the landlord to come through

Nasty letter from a lawyer: could be cheap/free, if you know a lawyer.

Filing Small claims action: they may pay off, no-show, or send a shyster to contest (I've never heard of the last one happening, but it's a risk you take).

I suggest you search reddit for that landlord/apartment building, and contact people with similar experiences (or else ask other tenants of the building, yelp and apartments.com are potential sources), they will be able to give you more practical advice. You could also edit your post or create a new one under a pseudonym asking for similar experiences with "XYZ landlord." The Point in Silver Spring had many stories similar to yours...

Make sure you warn others by posting to same.