British Airways Put me on a flight somewhere else and didn't give my full money for taxi Nationwide

 British airways had me booked in for a flight to Glasgow airport from Heathrow airport after traveling from New York they then told me my flight to Glasgow had been canceled so the next flight was at 16:30 it was only 07:00 so they sent me to Edinburgh and told me my expenses would be paid. So I got a taxi that cost me £124.80 and I sent British Airways the receipt and they have told me all I can get is £50.00 so because of there mistake I lose out on £74.80 I don't think company's with a turnover they make every year should be getting away with this!