Kombi tariff beneficial or not?

Dears,

When I had a contract with O2, they gave me two sim cards with two different tarif, the one called O2 free M is the what actually I asked from O2. However, they gave me another tarif called O2 my Data S, which only have 1gb internet and that is all, no minutes. My question is: Am I paying extra money for this O2 my Data S? I mean, now I am paying around 33EUR for my hardware, 11.98Eur for tariffs. Will this amount decrease if I stop/cancel O2 my data S, which I am not using it at all? or is it actually possible to cancel this O2 my data S before my contract time ends?

SIncerely Yours,

Aman!