Problem with Uniden TRU8885-2 cordless phone
 

I bought this "open box" phone via eBay, and when it arrived one of the
headsets had a dead earpiece. I sent the handset back to the seller for an
exchange, and he sent another handset.

Problem is, that handset is still registered with its original base unit,
and will not de-register because it can't find that original base unit! It
will not recognize my base unit. Removing power makes no difference - it was
several days in transit with no battery.

I'm probably going to have to send it back yet again, but I'd rather avoid
that if possible.

Anyone have any ideas how to deal with this?