Complex sentence: Officially the "Reichsmusikkammer" (Reichs Music Chamber) supported dance music that bore some traits of Swing, but listening to foreign stations, which regularly played jazz, was penalised from 1939 on.
Split into simpler sentences: Officially the "Reichsmusikkammer" (Reichs Music Chamber) supported dance music that bore some traits of Swing. But listening to foreign stations, which regularly played jazz, was penalised from 1939 on.