Not necessarily. I bought content from another model previously but unfortunately, she closed her account before I had a chance to download that content and now I can no longer access it.
if it's a ppv you unlocked you should still have it under the purchased tab. if it was just a message then it's gone. the other possibility is someone in the content wasn't tagged and onlyfans system somehow detected that and deleted it. contact support. you might be able to get the content back but most likely you'll get a refund.