Do Not Join - Misleading Sales consultants

On 5 Dec we visited Ushaka Marine in Durban and were approached by a sales consultant close to the village entry who had vouchers. We should have known better and just ignored him but he intentionally misled us into believing that my wife had won a voucher for free scuba diving and that I had won the jackpot prize (either a TV, cash etc). I didn't expect a world renowned venue to permit a co. that ****s people into signing contracts to operate from their premises so we entertained the sales consultants. After a presentation we signed a contract and money was deducted from my account. I was ok with paying the deposit because the contract said I had 5 days to ask for a refund. When we tried to use the vouchers we won we realized that they were not as pitched, the scuba diving voucher is actually for theory lessons you need to book not the practical as stated. We became suspicious and did some internet searches later and found all the people who had been ****med. After asking for a refund the company now wants me to send them over email my Credit Card nu, Expiration and CVV which is not safe. They refuse to refund to my account nu stating that is their process. ****************.