How to understand why Rostelecom blocked the site?

Question

Computer networks

For the first time I came across a site that was in the register of banned. And ironically it was one of my sites.
The usual site of a small commercial company providing consulting services.

I have mobile Internet from Rostelecom, and it turned out that the site (and a couple next to it) are blocked only from Rostelecom.
In the registry of prohibited sites, neither the domain nor the IP was found, but the site is still blocked.

What do you advise to do?

UPD: Everything has already been decided, most likely the hoster himself solved the problem.

Answer 1

In the registry of prohibited sites, neither the domain nor the IP was found, but the site is still blocked.

If you have shared hosting, then the site of the culprit could have already been removed from the hosting, also removed it from the registry, but Rostelecom may slow down.
In any case, contact the host, he most likely knows who the culprit is.

Answer 2

Is the site hosted on shared hosting? i.e. perhaps Rostelecom blocked all the sites hosted on it by your provider by IP at once.
What to do? At least angrily turn to the culprit, ... in writing (paper, Russian post, with confirmation of delivery, personally to the boss / ...), by phone call, etc. Also contact your ISP and your hosting provider! They, too, can be in the know and also contribute to solving the problem.
It is clear that almost certainly nothing will change. But, if only to remain silent, nothing will change for sure, and so an active position will be shown and perhaps something will change for the better.