Thanks for all the replies.
It certinly isn't lack of tension on the twine - if anything I thought it had too much. It sounds like the "wipe" action and possibly the knife is the big issue here.
I haven't paid the dealership, the guy finished working on it Friday and left early to go deer hunting without figuring the bill.
I did agree with them that the chains needed replaced - lots of wear on them and in some cases there was so much slack you couldn't get proper tension. I didn't want to break a chain and cause it to lose time and destroy the baler.