Partial refund received?

Last week i upgraded my membership in chess.com from gold to diamond (from 30$ to 100$) After a day i regreted and asked apple for a full refund. of the purchase (100$( Yesterday i received a notification from apple that says refund received but It seems like only partial amount (less than 10$). My gold subscription was about to end in November so maybe apple refunded my for the remaining 3 months? How can i proceed with apple as my request is closed?