For Sofort chargebacks there is no facilitated dispute management.
There is no automated way to defend and reverse chargebacks, e.g. there is no interbank scheme (as there is for cards, like Visa and MasterCard) that facilitates this process.
We would like to advise you to contact the shopper to resolve disputes on Sofort payments.
What are the alternatives if merchants cannot handle Sofort chargebacks?
Klarna offers a variant of Sofort where they take the chargeback risk. Note that there are downsides of using secured Sofort via Klarna (higher costs, lower auth rates and more integration effort) due to the addition of shopper data and invoice lines.
Another alternative is the use of direct online banking schemes Giropay and EPS, which are guaranteed payment methods.