TSA Lock locked open and won't reset.
 

I'm not sure if this is in the right place? My case was opened by the TSA (built in lock), the case was zipped up but the latches weren't engaged and the case wasn't relocked. Now the case opens on any combination and won't reset. The reset button is pressed in.

Is there any way to fix this or does it need a TSA key to relock the case?

Thanks.

$20 says they've broken it beyond repair.

Ask the bag / lock manufacturer. There is nothing special about these items other than that TSA has a key.

Next time, save the money and don't lock your bags.

Maybe the bag/lock manufacturer or a repair shop can fix/replace the lock. Either way, consider the following to make a claim for up to full value of the empty suitcase and/or repair/replacement cost:

https://www.tsa.gov/travel/passenger-support/claims

No guarantee of success.

If the zips still work then zip them up and use a cable/zip tie to hold them together and stop them opening (with a minor security function too) each time you use the bag. TSA may cut the ties to inspect the bag, but I always include half a dozen extra inside the bag and TSA has always taken the time to use one to re-seal the zippers.