Looks like you went to an expensive repair shop.
I just did a search, and found the replacement parts along with the tools to do the job for the Lumia 830 on Amazon.com for $17.99 with free shipping. Kind of makes you mad at the shop, eh? Of course, you need a bit of skill to do the job, but it's not that difficult. The service manual is available for download as a PDF where it gives pictures and instructions on replacing those parts.
You may want to look into a DIY job if it ever occurs again.
However, I always get a Tempered Glass Screen Protector for my phones. If the phone is dropped where the screen would break, the tempered glass will break/shatter, which can then be peeled off like a sheet of safety glass and it will protect the underlying screen from receiving any damage. Then you just buy a new Tempered Glass to replace the one that broke, and it's easy to install yourself. Feels like the original glass, usually with the oleophobic coating. Something to consider.