Resignation without notice while on vacation

Hello there,

While on duty, my knee got twisted back in November 2017. In Feb 2019, it started to give me more trouble and I did surgery in March 2019. Now, I can't return to my duty.

So I sent a resignation letter but my manager said to me I can't resgin as I'm on vacation leave. They want me to work for one month.

Is there is any way you can show me a way out?