Wrong calculator quoted and sent

I called the call center to request for a quote so that I can send it to my company as they are the ones paying , I was told to send an email and I did exactly that, after waiting for 2 weeks for my books and calculator when they deliver I noticed that they sent me the wrong calculator and I specifically requested for a financial calculator not a scientific calculator. Now I'm told I have to top up with +- R 400 for them to send me a financial calculator. I feel that it's not my fault that the wrong calculator was sent ... I don't have the money that's why my company is paying for my fees and books, why should I pay because your stuff was *********** . Please fix this , I have assignments due next week and I don't have a calculator because of your *********** stuff.