Margen
Your bank has an obligation almost nobody claims: if a direct debit arrives with an amount you were not expecting, or from a company you already left, you can order it refunded for 8 weeks from the debit date, without explaining why. It is not a favour from the clerk and it does not depend on the company agreeing. It is written into the SEPA Core direct debit scheme, used by every bank in the euro area, and into Spain's Royal Decree-Law 19/2018 on payment services, which also gives you 13 months when the charge was never authorised at all.
The small print, which is where people get hurt: returning the debit does not cancel the contract. The company can present it again next month, add its own recovery fees and, if it was a loan, register the missed payment. The returned debit gets your money back and leaves you a dated piece of evidence; you still have to cancel, in writing. With numbers: if they have been taking 39.90 euros for twelve months, that is 478.80 euros, but only the last two debits fit inside the 8 weeks: 79.80 euros the fast way, and the rest by written claim.
Open your banking app, find the transaction and the "return direct debit" button. If it is not there, call and ask, in these words, for "the refund of the SEPA direct debit, which is inside the 8 weeks": that sentence ends the argument, and all the bank has left to do is carry it out.