kitten nightmare

I had such high hopes for this blog.... but since I got the kittens I have had nothing but bad luck. Milo kept pooping all over the floor... so I bought a bigger litter box hoping it would be more appealing... then after a few days I realized if he was pooping outside the litter box
he was most likely peeing outside of it too... so he was moved into the bathroom. Then once I confirmed that he was in fact not using the litter box at all I started looking up tips online. My sister, a vet tech, said it was probably not a urinary tract infection as suggested online and little other help was available so I started looking into ways to train or retrain him. I tried moving the litter box to an area of the room he commonly used but he still refused it. I tried playing in the litter with a pen to make it seem fun and inviting (as suggested online) and unless I caught him mid act and moved him into it Milo wouldn't use it. As I got more and more frustrated I turned to Harley to keep me company (though I did put them together every day or so so they could play). Because I had put the small litter box that I originally had used in the bathroom with Milo so I would not upset Harley's habits I thought a larger one might help (he seemed to 'go' around it a lot). I bought another larger litter box and urine remover spray for the carpets and such. And since Milo would run through the mess in the bathroom and spread... stuff... all over I bought a wet swiffer to clean things up so I could use the bathroom as well. My sister suggested putting them in a cage when I was not around but I hated the idea of locking them up because they love running around.... Tonight, however, I came in the 'cat room' to watch House and keep Harley company since she seemed so lonely without her brother and and she went over to this sheet that was balled up that they often play in and pooped. right there in front of me. I checked the blanket and she had already pooped and peed in it earlier. So I put her in the bathroom with Milo. I wanted to make this site so people to vicariously have kittens all the time and share in my excitement and fun but so far this fostering thing has been anything but fun. I mean its super cute to watch kittens run around and awesome when they snuggle up with you but seriously- I cannot figure out what to do with these two.... all my other cats have just known to use the litter box. I think it's time to throw in the towel...