Internet ****

I have a problem getting service from Titan in Durban South Africa, they gave a quote followed by a proforma invoice, wich I paid in full. Then I got a message to pay a further R10 350 of wich R10 000 would be refundable on delivery? I imediatly stopped the sale and requested my 100% refund as per the quote and web advert. Now I am getting no response from them. People please be carefull of such companies on line.