errr
I hate to say this but I don't think piggies are ever supposed to just come to you unless you've got something really tasty. I've heard of it but it's rare. The article I read said that you have to do things to make them interract with you but not frighten them.
<a href="
https://pages.zdnet.com/mooble_99/thepigshed/id2.html" target="top">pages.zdnet.com/mooble_99/thepigshed/id2.html</a>
About halfway down this page is the taming technique that I used. I cannot say whether it is "right" or not. I can only say that it worked for me.
It basically tells you to do everything in steps to get them more and more comfortable with you a couple days at a time. I would also suggest that when trying to pet them or offer them food, make sure you are not towering over them. You want your hand to be lower than their eyes and move slowly. Also try petting and feeding at the same time. Sometimes they'll stick around for the food and realize that you're ok.
Maybe when they stay and lets you pet them a couple times you can start picking them up. But do it quickly so that they don't have a chance for flight to kick in :evil: If you have to chase them it'll just be a big scary experience. The only good thing I found from buying a store cage is that it's so small that they can't go too far so it's not all that chaotic so they got used to me quickly ahahhaha
Now my piggies will accept food from my hand, and one will ocassionally let me pet her for a long time while she eats hay and lets me pick her up on very rare ocassions.
You can also try giving them an article of clothing that you've recently worn to snuggle with if you're a cuddly type. I didn't do this with my GPs but I did it with my short tailed opossum and it worked.
If you try some of this, or if you don't, let us know how it goes!
Luck!