Sorry you had to deal with that! There are some sad arseholes who do this for a laugh - they have no intention of going through with it, they just want to have a wank later and feel smug about his they "got one over" on you.
I've been in sex work 5 years now and I think I've had 5 walkers, so I think 1 in ten years means you're doing really good! I'm in the mature niche and used to be plus sized as well, so perhaps that increases the incidence of arseholes, I don't know.
If your photos are accurate and your profile is up to date on age, dress size, boob size etc then I really wouldn't let this dick head get to you.
I know it's horrible though! I still remember an absolute wanker who literally looked me up and down like I was hideous and sneered "ugh no thanks" and walked off.
Have you looked yours up on client eye? He may have a pattern of doing this.