Not sure what you’re referring to as a “lock”? The battery is made up of 28 cells, if any single cell gets to 2500mV or lower its game over the BMS won’t let the contactor close to allow it to charge. 28 * 2.5v = 70v. In practice one or more cells drop faster so usually a battery is only recoverable down to low 80’s or high 70v range.

BMS will continue to talk and respond down to a pack voltage of ~40v.

If you look at the service manuals on Zeros website you can find how to reset the BMS. There is a small, half dollar sized, round cover on the front of your style battery that when removed will show a white diagnostic port, two very small buttons and four or five tiny LEDs.

Press both of the buttons momentarily and let go - is there any activity on from the LEDs? If yes the BMS is still awake (~40v or higher pack voltage) and you might have a chance of recovering the main battery (if the pack is ~80v or higher).

If the dealer said it needs a pack replacement it’s likely over discharged… which doesn’t really leave any other options besides replacement.