1. Remove is not necessary, but you need to have Account|Server Settings|Local Directory point to the correct account.
2.The account folders are hidden, by default. It is not clear that you know this.
A backup program would not backup hidden folders (mine doesn't, and I have to copy the folders out in the open).
3. The files of the account are not deleted. The are still on the hard drive. So, if your account was, originally, of the type: firstname.lastname@example.org
, a second account would be email@example.com
op.isp.net, and firstname.lastname@example.org
-1. Please refer to this:link