Petrus De paysafecard storting werkt helaas niet na toebehoren.
Make sure to not confuse paysafecard with paysafecash. Only the latter can be used for cash deposits. Indeed in certain countries like The Netherlands, it seems like some partnered stores aren't fulfilling their contractual obligations correctly.
Other ways to store cash might be to put it on another bank account and then send the money to the bunq account via bank transfer. Or there are also GWK Travelex ATMs that support deposits to all kinds of bank accounts including bunq, but they're pretty costly. Another alternative, if you live close to the border or if you're traveling, is to go to Germany and use Viacash/Barzahlen. The partner stores of Viacash in Germany work a lot more reliably.