Glen PNS GROUP does not care about people or terms and conditions on quotes

So Last week a man by the name of Glen his email adress glenb@pns.co.za ask for an alarm system , i send him a quote he called me back and said no he just wants a basic system so what do i do Mr nice guy i said you know what i will sell you the alarm at cost price and only charge you750 for installation which in the end i charge him 500 for installation and i in fact send him the quotation direct from the suppliers , the next morning he came back on whatsup and said it sounds good i will go for the alarm system , on our quotes it stipulates the clients must pay a deposit but surely Glen must realise us buying him and selling it to him at cost he must pay the stock money , so what does he do he lets me sa sales man buy the stock out of my pocket and till now does not give me my money back (refund) me , so i am not a rich man and then sunday he comes back on whatsup and says he does not do business like this first install the alarm and then he will pay , now it the the silly season every one is rushing to go on holiday so we are also running around and his installation will probably only be done in a week or so's time now i am out of pocket because i trusted a man that seemed like a gentleman but believe me if you see the emails every but Glenn i hope you feel ashamed of what you are doing then its seems hes a big shot at PNS GROUP and its 2000 odd rand so for him its nothing for me its a fortune