Bad Service

If I could do a accurate rating on the system it will be 0. I've been struggling with jet since August. Everytime when I want to pay my account their system is off, and due to this problem on their side I cannot pay. They have charge me interest on my account with the amount of almost R400 where my instalment is only R84.00. No one can assist me at the store and their head office and customer service phones are just ringing. This is unexceptable.