Account import works fine, you're just formatting it incorrectly - here is a
TEMPLATE SPREADSHEET to mass import accounts for MassPlanner (works for IG/FB). Just fill fields, and drag F column down to generate the MP friendly import text - copy F column and save in a .txt or .csv file, then mass import in MP.
@coitza
RE: Phone number "submit bug", The phone number glitch where it says submitted but resets isn't actually a glitch at all, either IG doesn't like your phone number provider (lookup on telcodata.us) or your IP is bad. It works fine using clean numbers/providers from clean IPs.