714,032 pageviews by Microsoft IP number to our shopping cart in 3 days: what’s going on?

Our website ecommerce/shopping cart link received
from bl1sch4081711.phx.gbl (65.55.107.116) the following:

March 13, 2008: 100,505 pageviews

March 14, 2008: 375,080 pageviews

Normally we receive a few hundred pageviews each day to the ecommerce/shopping cart link.

The tying up of our ecommerce/shopping cart raises special concerns.

A DNS lookup leads a Microsoft IP number, but with this note:
“Could be forged: hostname bl1sch4081711.phx.gbl. does not exist.”

Any suggestions, ideas?

Thanks,

ET