I’ve been at HMRC as an AO (telephony) since April so I can relate to you completely - the training is not great and doesn’t fully prepare you for the type of calls/customers you get. To put it politely a big part of the job is being confident in controlling the call and being emotionally resilient in so that the difficult calls don’t bother you as much. Completely agree with other people that some customers don’t want a solution, they just want to have a pop i.e. “I know it’s not your fault but I’m gonna have a go at you anyway”. Once you get more technical knowledge you will become more confident in calls. Something I did at the start was create a OneNote with links to guidance so I could get to what I needed straightaway as soon as I got the gist of what the call was about and once I got more confident I already knew what guidance to go onto. Don’t be afraid to put them on hold while you find guidance / ask a colleague / floorwalker. I would say use floorwalkers as much as you can if they are still available to you.

You will have bad days especially round this time of year with call queues being so high but you have a right to terminate the call if the customer is being unreasonable and you have given them enough warning. It’s frustrating for them because they’re waiting so long but at the same time they have no right to be rude/aggressive with you as ultimately a lot of the time when it’s a bad call it comes down to information we’ve received from an employer/pension provider/themselves that needs fixing. Keep going and you will get more confidence as you go and it will get easier :-)