Hello,
You have no reason to send box to reseller. If box was damaged during wrong cables useage it's not a warranty situation.
FT232 chip available everywhere, f.e. here:
http://www.ftdichip.com/
If FT232 chip damaged you still can use box as a dongle (with smart-card inside) but can't use it as usb-rs232 converter and COM port connection via box will be unavailable.