This happens to me all the time. I'll contact a provider, send her my references in my first message to her. She'll get back to me saying that my references are not responding to her and maybe they're out of town or otherwise busy?
So I contact my references myself and they pick up right away, very pleasant and very pushy too, telling me they miss me so much and want to see me that very day. When I ask if they received reference requests on my behalf, their tone immediately changes, they become surly and reticent, make some excuse about their phone/computer not working, and quickly end their call with me.
I've also noticed that it's usually the less established gals who are not that successful who play these petty games. On the other hand, one of my references who doesn't play such games and is always reference friendly is Sherry of DFW. That's why I have so much respect for Sherry.