what she wanted after moving out is that I cancel the contract

1. The American lady wrote me a letter of 4 pages, requesting me to cancel the signed contract. Otherwise, she sued me.

And she didn't pay.

She is a technical writer doing part-time job with different companies.

2. To reply to her, I said "you paid rent of 11 days".
She further threatened to sue me, if I don't cancel the written contract with her.