You can take out the quilting & redo it. I do quilting on a longarm machine, and 90% of customers will say, "Do what you want, use a thread you think looks good." Scary thought, those words are.
This is really not the longarm operator nor you at fault...it's miscomunication/misconception.
Next time, wether you use this person or not...get some ideas of what you want on the quilt...webshots is great for this. Do a search for Star Quilt...lots will come up...find some close in design and color as yours...then decide what you like.
Let the quilter know what you want, what color thread, design, etc.
Did you pay for a basic all over design, semi custom, or custom? I think the all over stars desgin would have worked as a basic all over design..but in white, or a light silver thread...maybe 60 wt, so the thread would blend into the quilt more.
your 2nd quilt looks ok for what I can see. it's hard to tell without a closeup of the stitching.