Order received short, refuse to credit or replace

Ordered a bottle of 90 capsules, only received 29 in a sealed bottle. Sent it back, got a new bottle of 90 - only to find that there were only 30 capsules. Was told that the item is non-returnable, so will not take back and credit, nor will they supply the missing 60 capsules. Their advert on their website and app clearly showed a bottle of 90 capsules, and the sealed bottle also says 90! This is false advertising and misleading, but they now will not respond to any of my messages. Incidentally, they have now pulled the product off their site!