Constance Corleone -- who owns an extension line called Bella Dream Hair -- filed the case, claiming Tami's rep contacted her last September and asked to try out Constance's product.

According to the suit, Constance obliged, and then was horrified to learn Tami had fired up her own extension line under the name, Curls By Roman. What's worse, Constance claims, Tami was advertising her line with a pic of her wearing Constance's extensions.

Thus began a serious of very funny tweets, including one from Tami which read, "Fraudulent people trying to take credit NOT. People trying to take credit for this hair. WTF they crazy."

After some back and forth, with Constance demanding that Tami send her extensions back to her, Tami tweeted, "Mad that I already mailed that S**T back2u cuz I got they address-would took it to Constance myself lying bitch."

Constance is suing for more than $500k.