Haven't been able to purchase diamonds for almost a year now?

everytime I try to buy diamonds I get a message to speak to customer service? ive talked to the card people and they told me to tell you just run the charge again,, SO what customer service do they want me to talk with? I have done the thing typing on the game about problems,, they tell me THEY are looking into it but after so long its gone and NO REPLY.. so now where do I go?