As Delphinium says you have to be really sure that it is Norton itself you are dealing with since there third parties out there who may describe themselves as authorized and who charge for support that Norton itself does not.
If you Google be careful about the entries at the top of the listing which are paid advertisements and although I do see genuine Norton there I also see third parties ....
The only "danger" I see reported here from time to time is when they take control of your computer, what they do requires a reboot and this loses the internet connection so you can be left with a machine that may or may not work ..... and it may be difficult to get back to the people at Norton who were working on the problem with you.
I'd advise anyone to outline the problem here first and see if we can help you to resolve it yourself ..... there are a lot of experienced users here!