Refund

Hi I bought a return ticket from Groningen to Nijmegen yesterday.  I managed to cover a dingle route and had trains cancelled for the after up until Monday 4the April,  2022. This made me stranded and had my return ticket expire.  This morning I had to purchase a single route ticket to travel.  Since the fault for the cancelled trains was not as a result of me as customer,  I am therefore kindly asking for a part refund on the part of the unused return route.  The ticket costed me 55.88 euros