about the subscription

Hi, I bought my NS card in February 2022, it got lost on august 29. And I blocked my card and ordered a new one. Till I lost my card I din have any issues with the subscription. After I got my new one, the lady I spoke with about the blocking and the new card said there will be no change in the subscription only the card number will be changed. But for October month I pay like 689. And for the next month, I changed my subscription to 362 but I could add my subscription for the. For this month I have to pay nearly 800 euros. I am an international student, so paying so many euros every month is hard. And I wanna know why could not add a subscription from the month of September to November

regards

sheena