Not well inform about Edgars account

i opened an account with Edgars (The Glen) last week and was not well informed about how the account works. I asked questions as i realised that information was not being given to me about how an the acc works. I was asked whether i wanted to pay over 6 or 12 months but was not told that with the 12 months option i pay interest and i chose the 12 months option. I only learned about the interest when i read the terms and conditions slip you get after opening an acc. I queried this and was told that it would be changed at the till on my first purchase, but at the till i was told that only Edgars head office can and would change my acc option to 6 months as i have not paid any instalment. Head Office said they can't help me as the acc was open on a 12 month option. Due to insufficient information i chose this payment plan and now that i know i don't want it. I called Edgars to have someone call me and explain how the acc works because that was not done when i opened the acc and no one has explained to me till today. Jet store employees and colleagues have informed me about how the acc works, but Edgars has not done this but rather shot down every suggestion i made to fix my problem.