You might want to polish up that excuse before you contact Flippa.
What are the odds out of the thousands if not millions of IPs available for public use that another random person would use the same IP you used for the purpose of activity on Flippa? What are the odds they'd visit ANY WEBSITE you visit as another random person using a public IP? Now even if that million to one longshot comes through, what are the odds that person would share any of the same information you used on Flippa or even come across one of your auctions of Flippa when 2,000 others are running? That would be odds higher than hitting the Lottery.
Flippa is very liberal with practically every long term, high volume seller shilling their listings on a daily basis. It doesn't take a rocket scientist to see all the shill bidding going on. I won't share how to spot the shill bidding because I don't want scammers to change up their methods. Right now they're like shooting fish in a barrel and Flippa is catching on.
With that being said, don't insult them further with a lame excuse like you use a public IP that someone else might be using for Flippa purposes. Flippa isn't that large and remove the seller ids and the shilling IDs and you've removed 75% of their accounts.