Book Swapping

Well I've been using Paperbackswap © for a while and this past week have been having a problem with them that has me now looking for another book swapping site. See my sisters and mom are/were also on the site and from time to time my mom would call me up saying she was having problems logging in or with her computer and needed me to go in and check a book as mailed or see if any had been picked. My sister had just set up an account and had problems setting it up and wanted me to go in and set it up for her just in case it was her computer. Well we figured that it wasn't her computer it was her address because another sister had been living with her for a time and had set up an account through paperbackswap using her address...well this sister has since moved to another state but the first sisters address is still shown as having an account so she set one up using her mil's address who lives just down the street from her.
Okay so we figured all was good now and went on our little ways and suddenly mom im's me says that she cannot log in to her account. Well I try to log in to her account and cannot get in, then I try to log in to mine and cannot get in. My sisters all say they cannot get into theirs either. So off I send an email to paperbackswap and they send one back saying I've opened multiple accounts and thats not permitted.
Wow wait a minute, I only have one account. I send them an email back saying this and that my family members are having trouble too, and they all only have one account all of our accounts are at different mailing addresses in 3 different states. Well they come back and say that I'm managing all these accounts from the same computer and that they know the computer usage and which computer is being used and all that. Well I know that every computer leaves its address with every website visited... but I still have a few problems with this, one its not just one computer my mom has a computer my sisters each have a computer and I have a computer, so that's at least 3 different computers being used. Plus my sisters have used a library computer at times when they were having problems with their internet service so that adds more computers in the mix. Now if we assume there are a minimum of 4 computers being used its going to be impossible for the all the accounts to be accessed by only one computer. Another problem I have with what they said is saying that I set up multiple accounts. Now, why in the world would I set up 4 accounts in 3 different states. I'm not going to be driving 200 or 1200 miles to get books from my mom's and sisters houses and why would I have books sent there and then pay postage for them to send them to me when I would be able to get books sent to me for free.
Another thing if they are going by one account per computer (I had thought it was one account per household), what are they doing to those who use library or college computers. In largers cities there could be dozens of accounts being accessed from one computer. Do they close all these accounts down as well? If they are going by on account per computer, then I could possibly have two accounts for my house as long as I had two different computers hooked to the internet and only accessed each account seperately per computer. Actually I could have any number of computers hooked up and then have a seperate account per each computer.
Well this whole thing is silly and I think Paperbackswap© needs to look at how they are doing things because this just isn't right. So now I'm looking for other bookswapping sites. I've narrowed it down to Bookmooch.com and Titletrader.com. I know I have a couple readers out there in internet world. Do you have any opinions on these two sites?