1999 Dodge Caravan auxilllary belt comes off when driving i

I need any info you can give on 1999 dodge grand caravans. I have had to tow the van to a shop about 5 times now because the auxillary belt comes off in the rain. It is parked in a public lot now with no belt. I have spent a few hundred dollars already, replacing the belt,tensioner arm, idler, and pulley, in the hopes of getting and keeping it running. I called another local shop this morning and was told that there was an update out on these vehicles about this very problem and an after market kit was out to fix it ($300.00). If this is a well known problem why didn't dodge recall the vehicle and pay to fix it. As it stands now, it will cost me at atleast $550.00 to get the kit and labor to install it.