Bad Service / Wont refund me unless i send an e-mail with my card number and cvv number

I sent an e-mail to ********** on 11 May 2018 the night before i booked online and selected the wrong time so wanted to change the time. i waited about 2 days no response, then phoned them on 14 May 2018 to ask to make the time change was advised this was going to cost me R7.50 and they would need my card details so i did this over the phone but my card would not allow the transaction as it was to small of an amount which i advised them of this, so i asked what now he said i must phone my bank i told him that is just ridiculous to release R7.50 from my account for this he then told me he couldnt help me in any other way, so opted for a refund he then gave me the ********** e-mail which i then rep**** i have used that e-mail and no one has responded or contacted me on. so any way i e-mailed for my refund and still no one has responded on the e-mail. Eventually 7 days later i get a phone call (after posting on the FB) that i would have to e-mail my bank statement my booking ID and my card number & CVV. I am not comfortable disclosing my card details this way this is how ***** starts so i was told on Face Book that if i didnt do this they cant help me. *** so how do I get my money back becuase in the history of all refunds never have i had to e-mail my card number and cvv number sounds ***** and *********