What is Mayella's version of what happened? Which part of her testimony contradicts that of her father's?

She says she invited Tom in and wanted to pay him to fix a dresser. Her claim is that once he came inside, instead of fixing the dresser he took advantage of her. Although she obviously lies, and Atticus can prove that she lies, she refuses to change her story and finally shuts down and refuses to answer any more questions.

She claims that she asked Tom Robinson to chop up a chiffarobe (chest of drawers) and when her back was turned he took advantage of her, choked her, hit her, and had sexual intercourse with her. She claimed that she screamed and hollered until her father came from the woods where he was gathering kindle.

Short version: When she asked Tom to chop up a chiffarobe, he beat her and took advantage of her.