Leaf Blowers

I recently purchased a husq 50.2CC 2-cycle backpack and 3 qts. of the premium oil. Total bill was $322.94 at Lowes of Cookeville, TN,on 11-06-16. The clerk told me that if I purchased the oil I could get a 2 year extended warranty free by registering online. My transaction no# is: 67459817. What do I need to do? Thank you so much.