Im in a mess

in 1999 I got a private student loan through wells fargo. shortly after college I got married and moved updated all info with wells fargo. A few months went by never received a bill made a few automated payments on phone however they were attached with 5.00 phone payment processing fees. After calling numerous times to have address changed they never could send me proof a bill of some sort to my current address for the principal amount owed. So I thought private loan just let it float off my credit after 7 years. Well I disputed my credit report a little more then 6 months ago well after 7 years the wells fargo thing still on my credit.Apparently wells fargo lied and said I made a payment of 14 dollars before the statute of limitations on my credit elapsed I havent paid them in some time not 1 penny much less 14 dollars. Now wells fargo sold the debt to a third party collection agency after they charged the debt of through income taxes slimy bastards. Now third party collection agency is threatening to put a property lien on my parents house and garnish wages from them if wells fargo sold the debt off to some one else can they do that and since its not a federal student loan but a loan on the private sector do the same consequences apply with a wells fargo student loan vs. Federal student loans???