Noisy, stubborn, wobbly seat

Well I think I have ran across my first unicycling equipment problem. I have a new Torker DX and the seat is noisy, stubborn, and wobbly. I know one cause of the problems is that I am missing a nut, but today I tried taking the seat off the seat post and one of the nuts would loosen to a point then it would stop twisting off .

In the first place, dont tighten the nuts too tight. It might be too late now though.

Get an extra nut, put the seat on all straight and everything, and tighten the nuts untill their snug or a little bit tighter than snug.

thanks but any tips on getting the one stuck nut off.