Were there record stores that sold this music? Did these bands play in countries behind the iron curtain? Did they get radioplay?
I know in the USSR, the record labels like Melodiya would press select recordings from the west. Quite a few of these select recordings were disco so that would help explain Russia's rather persisting disco scene. Also of note, Russia uses the continental definition of disco. So Madonna and Samantha Fox are considered disco acts and get played on Disco radio channels there today.
Pirated recordings did sometimes make their way in, as one might expect with the reports of the black market thriving there. This would be either via tapes or records.
Blaster radios, such as those from Finland, Sweden, Denmark, West Berlin, Greece, and Turkey would have allowed people with radios to listen to Western music. People in Omsk would not have been so lucky.