Virtual credit card

I app**** for a virtual credit card and they approved same day after excepting my debicheck I realised there was 3 more debichecks to be expected so I forwarded an email to two of fasta email address requesting that I cancel my virtual card as I have not even used the card. They have no landline to contact only mail. I have not yet any response from them I'm afraid they gonna deduct money from my account if they don't cancel this card. No one replying to my emails as if I'm communicating with a ghost. Can you please assist me with this problem. I see they have fasta loans also but no contact numbers