British Airways - Pathetic

I am absolutely appalled by the utter incompetence of the agents at British Airways. We booked a flight to Dublin from Johannesburg, and we had a connecting flight at Heathrow. Ahead of time, I called the airline to confirm whether or not we would require transit Visas for the UK. The agent that I spoke to confidently insisted that because we would not be changing airlines and our bags would not go through customs at Heathrow, that there was no need for transit Visas, I asked 3 times if she was absolutely sure and requested it in writing only to be told that the call center agents are unable to do that, but it is policy and she is absolutely certain that we will not require the Visas. When we got the airport in Johannesburg we were turned away and refused boarding of the flight, due to our lack of UK Visas..... SERIOUSLY?????? HOW do British Airways' employees get away with giving out such misinformation????? We then had to spend a FORTUNE at the airport to book new flights with a different airline, via a country that does not require transit Visas. Needless to say, that British Airways is now finding every excuse under the sun to not refund me contrary to the fact that there is a RECORDED call with their agent clearly feeding me misinformation. It goes without saying that I absolutely WILL NOT recommend British Airways to a single soul on Earth!!!!