You can't take it off once someone has bid on it, unless you report it as damaged, or no longer available.
I list often, and I would never put the start price as anything less than the very minimum which I am prepared to pay for it.
If you should take it off now (for one of the above reasons) then you relist it again, you run the risk that the current high bidder will notice, and report you to eBay for sharp practice. I wouldn't risk that - just hope for the best. Have you got many watching it?