USPS TRACKING NUMBERS

Am I going crazy or why have none of the items i’ve shipped out’s tracking numbers updated. Someone on here said it’s a tech issue but it is completely unacceptable how Depop has not messaged buyers about this. They keep messaging me and I swear to them that I shipped. Also it is still allowing them to get refunds and they get refunded bc depop claims I didn’t shipped even though I DID