Call Sentry Credit, Inc to let them know that your credit report hasn't been updated correctly. If they don't fix it then send the proof to the CRA.
Did Advanta offer you a settlement before they sold your debt? I have an Advanta account that is currently 60 days past dued and I'm hoping that they will give me a settlement, but right now all they are saying is that they will transfer my files to their legal department and may bring a suit against me.