Needle threaded is stuck in up position will not return 830 bernina

See troubleshooting section of manual. It will help to resolve your issue.
BERNINA-830-Limited-Edition.pdf

Similarly you can use this manual
Bernina_830_831_832_adj.pdf - iFixit

Which Bernina 830 are you referring to? (Yeah, it was crazy of Bernina to use the same numbers to identify different models...). There is the old Bernina 830 Record and the new computerized Bernina 830.

Have you tried rethreading the machine? If so, be sure to ALWAYS RAISE the presser foot. Verify the thread path is correct.

Page 31 of the manual:

https://www.bernina.com/en-US/Support-US/Machines/BERNINA-8-Series/BERNINA-830

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Are you able to turn it by hand?

If it is the older Bernina 830 Record, could be some of the parts have seized due to lack of oil. Frequently, seldom used functions (levers, dials, feed dog control) are the first signs.

Wheel on right side that controls the needle up and down is very tight...

Be sure to move the dials/levers and apply oil there as well.

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Threading the BERNINA 880e 830e 820 Bernina Sewing Center Tampa

http://www.manualslib.com/manual/726261/Bernina-820.html?page=30

Bernina 830 880 Needle Threader Cleaning

Install a brand new needle. Verify that it is installed correctly and is facing straight forward. If it is still not threading properly, then something may be bent or out of place in the threader.

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Might be able to find a manual here:

BERNINA Support Machine and Accessories Finders and Software Support...

Make sure needle is inserted with the scarf(small indentation above needle eye) to the back and fully inserted. Otherwise it could be out of time which would require a technician.

Sounds like you need to adjust the tension. Probably a good idea to oil this older machine before you adjust. Also look for and clean out any lint or debris in bobbin case and around foot area.

Okay, my first take—because it fills bobbins "just fine"—is that the needle bar may be loose. You didn't specify what the service was for: was it just a clean and lube, or did you have a problem? Even with just a clean and lube, the needle-bar height may have needed adjusting, and the tech may not have tightened it securely. Does the needle bar move at all? even just a quick **** or two? If it acts like it is trying to move, but doesn't, that is probably the problem. 
Now, here's the bad news (always seems to be some of that with these kinds of things, eh?): That needle-bar height is critical, and it's not something I can just tell you how to do here. The second bit of bad news is that the problem wasn't discovered for a year, so any service warranty is long expired, by now (unless the owner or manager of the store is your bosom bud, or, you are one of his/her best customers).
The good news is, if the shop is reputable, you could return it to them, explain what happened, and ask how much they would charge just to adjust and secure that needle bar (although the machine could probably use some more oil, by now—because it has just been sitting, which is harder on them than if you use them regularly). If they are like the shop I worked for, they will be glad to give you a slightly discounted rate to preserve their reputation, and hopefully, your business relationship with them. They may even throw some oil on it for the same price. 
One more bit of good news, the Bernina 830 is one fine sewing machine. It is worth fixing, if any machine is. 
Hope this is helpful, and happy sewing!
Ken