refusing to exchange damaged goods

I bought a fridge, home theatre system, tv set and microwave on credit from Russell midrand, Goods were never delivered on time and when they did the fridge had dents all over. they then promised to come and exchange the fridge the next day and have never heard from them since then its been more than 2 weeks, I lodged a complaint internally long time ago and has never been resolved till now, instead I get calls from different individuals asking that i narrate my story , promising to follow up and disappear into thin air. Lately i get 5 harassing calls a day from their call centre insisting they want to well come me and they either transfer me to their co agents or drop the phone if I ask for their manager. please intervene.