Looks like the issue hasn't been resolved after all

Had a letter today from HMRC saying..

''You told us that for the tax year 2017-2018 you no longer need to send us a Self Assessment tax return.
We agree and withdraw the notice to complete a tax return we sent you for 2017-2018.
The original deadline dates for paying any tax you owe will remain in force. Where the deadline dates have passed, we will charge you penalties and interest on any tax you owe us.''

Despite me telling them I have email conformation from them, thanking me for for telling them I had stopped my self employment in December 2014.

I was then passed to three different departments over a 55 minute phone call, to be told they would pass my details on to some other department that would look into this and call me back within the next 5 working days. I told them I'm a lorry driver and cant answer my phone when I'm driving.
I also asked why I was told it was resolved and they would reimburse me the money they had taken from me when I called them 8 days ago.

To me it seems a pretty straight forward error on their behalf, that I'm getting penalised for, and after 3 phone calls to try and resolve the matter it seems like I'm p1ssing in the wind.

Is this common practice with them, or am I just an unlucky one?