dell laptop 2n1 7306 screen

It depends on what you mean by "top".  The hinges (i.e. top assembly) won't stay open?  The screen bezel?  

Have they replaced the bezel with the display?

@ejn63​ hi, thanks, the screen itself has popped out

Only the repair shop knows what they replaced, but if it was just the screen, it sounds like other components need replacement.  Presumably the shop has some type of warranty on its work, so contact them to have the repair completed properly.

You can buy an entire upper assembly for this model for $200-300, including the hinges, back cover and bezel.  If those haven't been replaced, the assembly probably should have been replaced as a unit.

how is the top of the screen attached - where the slider is for the camera?

The service manual makes it appear that the display panel isn't designed to be removed from the assembly.  Again, it's a question for the repair shop as to exactly what they replaced.

It's easy to break plastic tabs when disassembling the display assembly -- which is probably what happened.

See here for the service manual

https://www.dell.com/support/home/en-us/product-support/product/inspiron-13-7306-2-in-1-laptop/docs

thanks, It doesn't actually show how the screen is attached at the top? Do you, or anyone know?

Why not ask the shop that did the work?  Someone there had the system apart to replace the screen.

and replaced it incorrectly

If you look on EBay, there are images of the back cover showing screwholes--if the display pops out of the back cover, that may need to be replaced.  If it's the bezel that's popping out, the bezel may be damaged.  Either part seems plentiful on EBay for $50 each or less.

Otherwise, arrange a refund of the repair and order a complete display assembly including the back cover and bezel.