Step by step:
1. Create an account at https://www.multcloud.com/sign
2. Go to your account: https://www.multcloud.com/index.jsp
3. Open "Add Cloud Drives"
4. Select "WebDAV" and then Next
5. Config the WebDAV
Server (WebDAV Address): https://cloud.allsync.com/remote.php/webdav
Do you have an Pro Plan then is your WebDAV url as follow:
Repeat STEP 3 And setup your old cloud provider.
6. Open "Cloud Transfer"
7. Select the directory you want to transfer from and to (Allsync).
8. For Example: Backup your files from Dropbox. Click "Transfer Now" to continue.
9. Open the status page.
10. Remove your cloud accounts from multcloud.com after you finish. Go to "Cloud Explorer" and Right Click at the Cloud service name.