A sells B a car, B pays for the car and is then given the keys with the accepted instruction to pick up the car from a garage on a unspecified date. B has gets tied up in other business dealings and has to travel to another city to secure the deal. Corona happens and a national lockdown is imposed and now B can't return to get the car. B complains to A saying A has B's money but B still doesn't have the car. What effect does the national lockdown have on their contract?