Yep, just make sure everything's ok and wired right, and try, try again. Your EasyStar SHOULD be able to get so high you literally can't see it with no trouble at all! I suspect you may have a problem with your speed control (ESC). That could account for most all your plane-related symptoms. Why not take your speed control to a local hobby shop and have them give it a once-over with several motors?
Also, next time you work with your plane, check to be sure the ESC channel (channel 3 on the transmitter) isn't set to "Reverse". Not very likely, but not impossible either.
Don't let any of this sour you on the EasyStar! It is absolutely one of the BEST designed RC aircraft ever designed - I would place it in the top 5 without hesitation.
Flyer