S&W internal lock failure while engaged

I purchased a S&W 63-5 to replace the Ruger LCRX I own that previous snapped the transfer bar.

After picking it up from my FFL, I went home & shot 18 rounds of CCI quiet .22 to try it out. After that, I was giving it a once over & decided to see how the lock worked.

I turned the key to engage the lock & it slipped a little bit before engaging fully. When I tried to disengage the lock, the post that the keys go onto stripped & then broke off.

I took the side plate off & removed the spring that holds tension on the internal lock. I then tried to use brass shims and feeler guages to try & disengage the lock, but it's seized up tight.

Does anyone have a trick for removing the hammer w/ the lock engaged, or do I have to send it back to S&W?