So to check accuracy of the code,i tried with less permutaions and it took 30 sec around.Then I ran above code.This was the testing code---

from constraint import Problem, AllDifferentConstraint

# Basic setup with fewer constraints to check if it finds solutions quickly
problem = Problem()
customers = ["Freda", "Opal", "Penny", "Sarah", "Vicky"]


for i in range(1, 6):
    problem.addVariable(f"Customer_{i}", customers)


problem.addConstraint(AllDifferentConstraint(), [f"Customer_{i}" for i in range(1, 6)])


solutions = problem.getSolutions()


for solution in solutions:
    print(solution)