Bad customer service and a ripoff

I bought a bed and a fridge from Russells through Connect Financial solutions. I was double charged for transport and the items were delivered at the same address, at the same time. I signed a contract for 30 months yet my statements say 36 months and no one is fixing that. They charged 3 times the actual cost of a power plug they said ill get for free when buy the fridge. the branch blames Connect financial solutions and they blame the branch. No one is willing to help and am being sent from pillar to post. Bad service overall especially with the call centre agents. they dont update customer remarks on their system and I had to explain the story to 100 different agents, with no resolution. Their interest rates are insane. for items costing 10500 they want me to 28 000, and this is excluding the deposit of 1500 I paid at the store.