Complex sentence: After Soft Cell Signed to Some Bizzare Label he went on to manage Soft Cell, under a deal with Some Bizzare Phonogram their cover of "Tainted Love" topped the charts.
Split into simpler sentences: After Soft Cell signed to Some Bizzare, he went on to manage Soft Cell, under a deal with Phonogram. Their cover of "Tainted Love" topped the charts.