Conor was it the levelwind or the non levelwind version of the reel that you got?
If it's the levelwind version then your problem is probably to do with the knot that was used. An arbor knot tends to be the best one to attach the line to a multi or a fixed spool reel, is that what you used? If you didn't and want to do it again, just wind the line back off onto an empty fixed spool reel, redo the knot then wind it back on again.
If it's not very level then maybe you need to wind it off then back on again slowly and make sure you get it on level.
When you have it on, tape it up and spin the reel with the foot of the reel on the table with the reel on freespool, the reel shouldn't jump all over the table, and if it does then it's not balanced very well and will cause problems when casting.
A good site for how to work with this is Neil Mackelows tuning website.
http://neilmackellow.sea-angler.org/reel_tuning.html
Don't take it all too seriously or get too bedded down in that Conor, it's for performance casters, but look at the bit about balancing the spool and the bit about levelling the line, you can move onto the rest when you're a big hitter ;)
I know it's a sport mag of some sort you have so look at the bottom bit about the abu 6500ct mag.
Hope that helps a bit.