No responsibility taken

Went to purchase Broadine for fleas on my cat from Vetworld in Somerset Mall. The lady there informed me they did not have broadline and only have revolution but promised me it would have the same Results. It did not have any effect. When I contacted vet world 4 days later to inform them they told me to “contact the manufacturer” and did not take any responsibility even though they were the ones who recommended the ineffective product. I would never trust them to give any sort of care for my cat if they don’t even care that something as simple as flea spot on doesn’t work.Terrible service and attitude