Michele
It's unusual for the DWP to still carry out these bullying tactics but it does still happen as you have found our.
You can make a complaint to the DWP but outgoing calls are not normally recorded so it might end up being your word against theirs.
Complaining to the DWP As to the appeal, you don't need to do anything additional, the DWP will be automatically sent a copy of any testimony and evidence that you submit by the Tribunal Service.
The TS is independent of the DWP and your Tribunal panel will make its Decision based on all of the evidence before them and your testimony on the day,
Gordon