Misleading DebiCheck Mandate and Unauthorised Ongoing Deductions

I accepted this DebiCheck mandate while applying for a loan because I believed it was connected to the loan application. I was not clearly informed that I was signing up for a separate recurring paid service. Money continues to be deducted from my account, yet I do not know what service or rewards I am receiving. I demand immediate cancellation, a full refund of the deductions, and proof that the recurring charges were clearly explained to me before I accepted the mandate.