I would take it back first and explain exactly what is wrong. I try and do all of own basic set up stuff and it is both rewarding and frustrating. I can take a lot of things in life but a buzz on my guitar is not one of them. It takes me a long time to figure out how to fix them because I'm still a newbie when it comes to this. I don't mind spending money on having someone do something properly but when I give someone my guitar and tell them what I want I expect it to come back in the condition that I asked for and for me it usually hasn't happened that way. If you hand someone your guitar and ask for a set up and that's it then don't expect to be wowed by anyone's workmanship. If you go in and try and be as specific about what you want as you possibly can and it still ends up crappy then there's a problem. I don't think that you will ever regret learning how to work on your own guitar either way.