Wrong item and incorrect interest chardged

Good day I am traumatized by Homechoice. An agent at homechoice added an item that i was asking about to my account and when i recieved an sms saying that I must collect the item i called the contact center that i never ordered the router but they continued to charge me and they took between 4 to 5 months to collect the item. To make matters worse they were charging me interest for the account i am currently paying plus the routers interest as well now they are telling me that due to rates changing that's is why my account has accumulated so much interest bur by my understanding the monthly payments required by them includes interest as well and i am paying more. Homechoice is still charging me interest on the router. Even the statement that they forwarded to me just shows that they added extra amounts to make the money for router returned which is not my fault but the agents who useless and negligent. Now customer service is no help as well because he is explaining something he doesn't know. I have asked the numerous times to recalculate my account but to no avail. Homechoice is money making ponzy scheme