eyelash growth

I had eyelash extensions put on at a spa. The girl was trained about 6 mos. ago and does many sets a day. They were only $175.! I couldn't resist. I know you shouldn't go for CHEAP when getting extensions, but had they not been so cheap, they wouldn't even be an option for me. I have to have them filled every 2 weeks. The worst thing is they're so messy! They're not pretty and straight like in pictures. She said the reason for that is because natural lashes aren't straight, they go in different directions and so will your extension. They're nice for a few days, but then they go this way and that, some curl to the side, the end ones actually curl downward! The brand is Prima Diva. her glue isn't old, she says she uses up a bottle in 2 weeks. I just can't afford to go to a more expensive, experienced place! I want to keep doing them, but they look horrible after a few days. She puts primer on after. I have some too, but it doesn't straighten or turn them. Is she doing something wrong?!!

I need advice on Prima Diva professional eyelash extensions!?