OK, update to the previous post -- Ekosport/Kreitler has responded already. Here is their response:

I talked to my sales manager and technician regarding your
questions. In regards to the warranty, the documentation we have
shows that Al only supplied a 1 year warranty due to the fact that he
couldn't guarantee these rollers for a lifetime. Since you have been
such an avid customer we could do one of two things. First, since
money is tight at the moment, you can just use 2 PVC drums and 1
aluminum drum at this time. We would still offer you the discount
which would bring the cost of one Challenger drum to $XXX plus
shipping. My sales manager and I both suggest that you replace all
3 drums as soon as possible however. If you are willing to replace
all 3 drums at this time, he is willing to extend you a XXX discount at
this time, which would bring the cost down to $XXX for all 3 drums
and a new belt.

Please let me know how you would like to proceed.

Thanks

OK, it hurts to come up with even $XXX but that's a pretty fair offer. Maybe these people aren't so bad after all.