"Tang ina" is never been a short term word for putangina mo. It has a different meaning especial if you don't put "mo" at the end it means you're not referring to someone else. "Mo" means You.
generally it's just an expression when you're upset of yourself or something.
We should also have a rule about these people keep on posting random complains. To lessen the burden from you admins. Especially if it's proven wrong or just targeting another player waiting an opportunity to retaliate.