Corporation tax

I have recently sold my limited company and I would like to file corporation tax up to the day of sale. I wrote a letter and sent to HMRC on 12 November 2023 but still no reply. I used to use HMRC online service to file corporation tax and now the company handed over and I have no access to gateway and do it online. What can I do? Do I have responsibility to do so?

Hi Suk Poon,
Thank you for your query. 
Guidance about your responsibilities when you sell your company can be found herw:
Selling your business: your responsibilities
Please note that our current timescale for dealing with postal correspondence is 40 working days from the date of receipt. 
Thank you.