Sounds like you may need to contact Jolla for this one;
https://jolla.zendesk.com/hc/en-us and tell them what you have asked us.
In most cases, to remove a password, you need to know the password. I am to understand that recovery via Jolla Recovery Tool (Telnet) still won't work if you don't know the password that got set, so it sounds to me like a full reset is in order, but with help from Jolla.
I found this snippet of info here on JTC;
Notes:
For a description of the recovery tool options see this Answer below. For destructive options (e.g. resetting phone to factory settings which will return the device to ex factory state not only for Settings but the complete software version) your device lock code is requested. When you have mistyped it for 4 times, you have to wait for 24 h before you can retry. (Or reboot the device by removing USB connection and removing/reinstalling battery and then pressing the power button to reset the timer.) - As I stated earlier, recovery may not be