Unable to file end of year accounts and CT600 for corporation tax

We have been trying to access our business account to file end of year accounts and CT600 corporation tax for our business (which is in it's first year of trading) We get the following error when trying to sign in "You can't use this service Our records show that you're not authorised to use this service. If you're not registered for Corporation Tax You need to register for Corporation Tax on your Government Gateway account before you can use this service. Register for Corporation Tax services (opens in a new tab) If you're a tax agent This service is designed for individual use only. You can file using commercial Corporation Tax software (opens in a new tab), and you can still use your usual HMRC online services (opens in a new tab)." If I then follow the steps to add corporation tax to the business tax account I get the following message "There’s a problem This information does not exist for Corporation Tax, or it has already been used to request access to this tax or scheme. You should: check your details get help using HMRC online services" I really don't want to ring up to sort this out problem as it is a painful experience trying to contact HMRC by phone

Hi ,
 

Given the problems you have described I would refer you to 'Technical Support with HMRC Online services', available via GOV.UK. There is the option within this guidance to seek help 'online', alternatively there is an option to call HMRC. Although our phonelines can be busy, I would encourage you try different times in the day, sometimes when the lines first open, 8am, it may be quieter. Thank you .