I have dual employement of 28 days in past

Hi I have been in trouble I was working in X (mnc) and within 10 days of resignation I was relieved from my project and was on bench. I had an offer letter from Y organization. The HR of the Y organization has given me offer letter for 22 dec 2021 and My last working day in X organization was 19jan 2022. Now i have told the Y organization Hr about the last working day and also stated that I am on bench right now. she asked me to join and will be no issue in it. after 6 months of joining now i am trying to join otger organizations they are giving me 28 days of dual employment. i also made an email to Y organization stating that issue but unfortunately the recruiter has left the organization. what i can do now ? whatever i did was unknown to me as i just started my career i dont have any prior knowledge about dual employement and all. I blindly followed the HR words and joined the Y organization. i have already tried making statement that I was unaware of fact of dual employment and As i just started with my career i was unknown also i dont have any offer and it was covid third phase was coming so i joined organization.