doesn't/didn't?

[vkhu]

Turn this into reported speech
“This store doesn’t open on Sunday,” the man informed me.

->The man informed me that that store didn't open on Sunday

Should I really turn doesn't into didn't? I mean the fact that the store doesn't open on Sunday is always true right? If I remember correctly, someone once told me I should leave the verbs as they are if the fact is unchanging.

[Raymott]

Turn this into reported speech
“This store doesn’t open on Sunday,” the man informed me.

->The man informed me that that store didn't open on Sunday

Should I really turn doesn't into didn't? I mean the fact that the store doesn't open on Sunday is always true right? If I remember correctly, someone once told me I should leave the verbs as they are if the fact is unchanging.

“This store doesn’t open on Sunday." This is ambiguous. It could mean just this Sunday (ie. next Sunday). You should use 'Sundays'.
If the man meant just this Sunday, you'd say, "The man informed me that the store wouldn't open this Sunday."
If he meant Sundays (any Sunday), "The man informed me that the store doesn't/didn't open on Sundays."
So, you can use either.

[emsr2d2]

“This store doesn’t open on Sunday." This is ambiguous. It could mean just this Sunday (ie. next Sunday). You should use 'Sundays'.

That's interesting. If I wanted to tell someone that a shop wouldn't be open next Sunday, I would not use "doesn't open".

This shop won't be open on Sunday.
This shop won't open this Sunday.
This shop will be shut on Sunday.

As Raymott said "This shop doesn't open on Sundays" means that it is always closed on a Sunday.