Automailer does not limit the number of contacts or lists you can upload in your account, however, there are some general rules of thumb that you need to follow:
Automailer only accepts .CSV (Comma delimited) file format so make sure you save your file with the correct file format.
The maximum file size per list that the system will allow is only 14MB. If your file size is larger that 14MB, split it into 2 to fit the file limit.
The only requirement that the system has in terms of your list data is that your list MUST have a header called "Email". This is what will tell the system where to send your campaigns to.
To know more about how to format your list, read: How to Format Your .CSV File
In conclusion, Automailer does not limit you in terms of how many lists you upload. You may upload as many lists as you like as long as each list follows these rules. If you need any further assistance with the platform, feel free to contact customer support through the Support tab or email email@example.com.