Incorrect overcharge and refusal to correct.

I've been with Courier Guy for a couple of years and for the most part they have been ok. But recently almost every single one of my parcels have arrived with 20 - 50% of the items broken. This is despite careful bubble wrapping and using expensive strong boxes as well as fragile stickers. So I've had to pay to replace the broken items AND pay for a second delivery. I asked about having at least the courier charge refunded due to the obvious mishandling of the parcels and was refused. Then to top it off, last week I sent a parcel from Joburg to Parow. A small box weighing under 2kgs. The system quoted me R140 or something so I went ahead. Then I noticed my account was in the minus and discovered that they had charged me R280 (alsmost R300 for that small box) for that delivery. I argued on the cost and they insisted that it was correct due to the dimensions being different than what I had entered on the system. I entered the EXACT dimensions and weight they gave me and system quoted me R161. Despite being shown this, Anke Klein still refused to reverse the charge and insisted that the R280 was correct. I am not impressed with this recent service. And being charged almost R300 for a small, light parcel to go to Parow is absolute *******.