Using Odoo 15EE

A POS session won't load (stuck in opening control) due to a Price list error.

"An error occurred when loading product prices. Make sure all pricelists are available in the POS."

I think the problem could be that I deleted the default installed pricelists ... 

I cant change pricelist setting in POS while session is open and I can't load it to close it ... so stuck in an endless loop! 

How can I 'force' the session closed and/or reset the POS session?

What do I need to do to regenerate the default Odoo installed pricelist and/or remove all references to them in the POS system?