Account Increase without consent

Its been years since I have been with Sports Scene and every year they seem to try and increase my account credit without my consent. In 2014, it went to an extent that I wanted to take serious measures against them after taking time to complete a form at Markham indicating that I do not want any automatic credit increases. Times are hard and more and more people are limiting any unnecessary spending, my feeling is that the retail industry knows that this would mean less and less people are more conscious with taking extra credit as a result they try and do this automatically without getting consent from the individual to push their commitment. What irritates me the most is that they do not even take time to see whether or not you can afford to have your credit increased.