In the beginning, Swift seemed not interested in any credit for the song. She even writes the melody and parts of the song under a pseudonym. However, she is really hurt when Calvin tries to take all the creative portion and denounces her collaboration on the song entirely.
Inside sources close the songstress says that she did not want credit for the song, but felt betrayed when Calvin went to great length to hide her collaboration in the song. But after they broke up Swift let it slip that she was actually heavily involved in the creation of the song.
This led to Calvin going on a rampage on Twitter. "Calvin is furious with Swift for leaking the information, "said the Source. "He feels like Swift is attacking his career." Experts believe that such statements in such a critical time in his path may destroy him and understand the backlash he has unleashed. All the same, Swift is entitled to credit and more if she did collaborate with the song.
Swift moved on quickly and is in another relationship. Calvin did not spare any aspect of her life on Twitter. He attacked her new boyfriend, her friends, and family. This led to Swift completely disappearing from the public eye for two days straight.