What is halal amongst non tangible products

[jumpstart17253]

Assalam wa alaikum,

I work for a software company.
The company charges a fixed yearly fees to the customers.
This fees cover any software updates and any maintenance
required.

Question: Is it halal to charge this fees? The company is
not selling anything for the money it receives. There may
not be a software update and maintenance may or may not
be required to be carried out. So the customers may end up
having no benefit from the yearly charge they pay us.

Is this income to our company halal?
If a warranty is sold along with an OLD car, is that income halal?
If the audience don't like a movie, they go home unsatisfied, is that income halal?

Only mentioned because I feel they are similar scenarios.

May Allah reward you.

[Umm Malik]

I couldn't understand the question exactly if it in Arabic I could ask a scholar about it

[jumpstart17253]

i don;t know arabic. can any brother here translate it for me.