Ameritrade charges $10 per trade, But I get charged an...

Ameritrade charges $10 per trade, But I get charged an additional $25 for every LNGLF trade. I called and asked Ameritrade and they said they didn't know and it was not their fee, they speculated it was a charge for buying a foreign stock charged by the bank doing the buying, so Goldman Sachs maybe. I haven't noticed that same $25 fee with LNGLY, so I like LF but can't do multiple small trades of it and end up paying $35 a pop with Ameritrade's fee plus the extra $25.