Film not loading properly

The lines could be scratches in the negatives.

Have you looked CLOSELY at your negatives with a magnifier to see if the scratches are on your film?

And when you say "Serviced", do you mean "cleaned" also?

If you have scratched film, then return it to the place you got it serviced/cleaned and let the owner/manager know that you just had it serviced there and it's scratching your negatives.

If you have an automatic camera, this bit below will be of no help.

Assuming that your camera is a manual loader, it may be that you aren't putting enough film into the take up spool for it to catch.

Try putting a little more film into the take up spool when you are loading the camera, and MAKE SURE that the holes in the film LINE UP with the film sprockets.

Then after you close the film door and start advancing your film, look at the film rewind knob, if it isn't turning while you are winding in film, then your film hasn't caught in the take up spool.

Another way to tell if your film is advancing is to shoot a test shot, and then advance the film, and then lightly turn the rewind knob a bit.

You should be able to feel the tension of the film if it is loaded correctly.