Please identify the level of threat from this notification apparently displayed from Google Chrome

[Robert333]

I would like to know the level of threat and the solution (if the threat returns) from the following. These notifications started to appear in the bottom-right corner of the screen while running Chrome and remained on the screen after Chrome was closed.
I have a PC running Windows 8.1 with Google Chrome.
The Windows version means that Chrome cannot be updated.
I have Avast Free antivirus updated to the latest version.
Comodo Free Firewall.

These are the actions I have taken:
Restored the computer to a Restore Point dated prior to the apparent threats.
Then:
Full virus scan in Avast (configured for most sensitive scan) - no threats found.
Boot-time scan in Avast (prepared with additional definitions) - no threats found.
Malware Bytes Antimalware scan - no threats found related to this issue.
Spybot Search and Destroy Scan - Tracking traces found and removed.
Ccleaner - Set to Secure removal - Removed Cookies, temporary internet files, Temp files, etc.
Google Chrome - Deleted History (configured to “All Time”).

I have made an Internet search for the entity mentioned on the threatening notifications which is called “erfsoft.ru” [this displays as a link which is not intended to be any link in this post - do not click on it just in case!] and have found nothing. I understand that “ru” refers to the Russian Federation. Does the fact that nothing about this entity appearing in the Internet search for it I have made, perhaps therefore mean that someone may be targeting me as an individual, rather than it being a threat “in the field”?

I know nothing about any “payment” to which reference is made in the second image.

The following are screen-captures of the notifications. There are two images each of which shows two notifications:

[prokopes_]

Hi @Robert333, it seems you (probably accidentally) allowed push notifications from a suspicious website. The following article explains how to block such notifications: https://www.avast.com/c-turn-off-chrome-notifications

Btw, these notifications are not targeting you as an individual, they are generic push notifications malware/pup.

[Robert333]

Thank you “prokopes_Employee”.
I have disabled notifications in Chrome using the information to which you referred.
I suspect the website responsible was one where I was attempting to download an audio application, and therefore also where the button that allowed such push notifications was labeled “Download”, in other words for the application I was trying to download. I cannot examine the Google Chrome History for that date and time to try to identify the website as I felt obliged to delete that, as part of the actions I took.
I have not had such notifications since I carried out the actions to which I referred in my original message.
Thank you.