Paid for but not delivered

on 05/02/16 I bought 2 X (6 month showmax subscriptions) which should give me 12 months total but I only recieved one code on sms which only gave me 6 months. I am short a second code (6 months subscription). I have been backwards and forwards with \customer service\" who tell me the code sent was for 12 months but It only gave 6 months. How is it possible that a simple complaint like this can take over a month and still not been resolved? "