Access code problems

So I've completed my tax return, but I can't submit it because my HMRC app has now logged me out, and therefore I can't get an access code. I can't log back in to the app because I need an access code to do that. So I click the link that says "Problems with the app? You can get help". Then the two options are "Change how I get my access code" and "Try again later". The "try again later" option is not exactly very helpful, so I click the first option. Then I'm told to "Call the online services helpline" on 0300 200 3600. So I ring. And hold. And hold. And hold. And hold. And hold. Any suggestions? Is there no way I can ask for a new access code to be sent by SMS?

Hi Peter1981,

Ifyou are having difficulty contacting the Online Services Helpline by telephone, you can use the webchat offering using HMRC’s digital assistant
All contact methods can be found here 
Technical support with HMRC online services)

Thank you.