Wobbling back wheel

[luke8885]

would just like to say a big hello to everyone and please could someone help me. when the back wheel spins it has a slight movement up and down motion.plus both wheel at one certain point the disk rub i have took the bike into 3 different shops now and am getting real angry went and got me bike this morning told me everything was ok and now all my low gears are messed up keeps slipping and if u push hard on the pedal it jumps so to speak but the bike hardly been used and still has the problem. need to fix it myself but need some advice please. i have a cube acid comp