Kulula poor service and no refunds

I am disgusted in the service received from Kulula that I have been receiving

In December we booked a flight and called Kulula to confirm that the parcel we needed to transport was definitely allowed on the flight. They reassured us that it is allowed and so booked the flight. We would never have booked this flight if it wasn't allowed as the purpose of the flight was to get the parcel to Cape Town asap

At check in they then told my husband he isn't allowed to take this parcel and get a refund instead

I have been trying to get a refund on this return flight since then. Each time we call they then tell us they need to listen to the call from the start but have confirmed that it was said in the conversation this parcel is allowed on the flight initially, so where is my refund then?

We haven't had any feedback and when I called again today got told they will listen to the conversation again I'm still waiting and feel this is totally unacceptable