So a lady calls about some leaf removal. I tell her i'll cut her a deal if she allows me to mow her yard this summer. Well I tell her i'll do if for $50. So i do the leaf removal with me and one other guy for 9 hrs. Then she calls me today and tells me she has a kid thats going to mow her yard for $40 and i told her i'de do it for $60. So i did $350 of leaf removal for $50 and didnt even get the yard.. what can i do to prevent this from happening again?