Can't do much for you friend. If you don't accept the book of Hebrews and the testimony of Paul as authoritative then nothing I can say will convince you otherwise.
Hebrews is a big book. Try to be more specific. Especially, try to find a place where God said He was setting aside just a portion of the Levitical code and keeping enough for ersatz holy days. That should be easy, as I said Hebrews is a big book.