I think this goes both ways... Has anyone been "tire-kicked" by sellers?

A lot of people know I collect certain players or am shopping for certain bats, so I get solicited to purchase items quite frequently. There have been more than a handful of times somebody has approached me with an item to sell and I've been dragged along for upwards of two or three years on a couple of items. They've said they want to sell an item, I review it and make an offer, the seller agrees the terms were fair and accepts the terms, but they have just never decided to part with it. I send payment and its refunded, I ask to confirm their paypal address and they tell me to hold off. Every few months they check back in and ask if I am still interested and I indicate the offer stands and I am ready to pay and they back out of selling again.