Refusal of device repair as it's vodacoms fault

I took my phone to the vodacom store at blue valley mall I'm the Reeds due it being their fault causing damage to the back cover of my phone which has been replaced twice still not the original back cover that was with the phone however a rude lady advised I leave the rubber bands 9n for 24 hours before removing it ever since removing rubber bands after 24 hours has caused tremendous damage to my phone and they refuse to acknowledge the damages they caused and refuse to repair it I will also log a complaint with vodacom head office