Delta Airlines won’t give me my credit for purchased ticket

Had to cancel my flight and postponed it to February 2024. When February came the flight was cancelled, which was not a problem. I contacted Expedia and Delta Airlines and they said my flight will be credited, but will expire in October 2024. It has been a month now, I’m struggling to get a hold of Delta, the lady I spoke to was very rude and said she can’t help me. The ticket was very expensive, not to mention postponing, which cost more. Now I’m being told they don’t have my credits. This is absurd! The ticket is expiring in a month and they won’t do anything to help me. I requested them to phone me, still no response after a month. Please do yourself a favor and don’t fly with Delta.