Shocking customer service and damaged bag along with ****** items.

I am absolutely disgusted at Mango Airlines for their poor service provided to people.... We arrived from Cape Town on the 24th of December (Christmas Eve) with 2 bags, 1 came out the other 1 took a long time to come out. As we got home I could not open the bag that took a while to come out, I could not open it as it was damaged along with items inside unwrapped and ******... They decided to unwrap a gift and take out a wallet I had gotten for my husband in a tin. The tin was put back into the bag with the wallet ******..... All I have asked Mango to do was check the cameras and replace my bag. They tell me I need a police case number in order for me to check the cameras as they see no discrepancies on the cameras on the night in question? So firstly I am lying is what they are telling me and now they refuse to replace my bag that their staff damaged?? Bags are not cheap! I would like some answers please?