Wife took a call from work for me while I was on leave and told them not to ring again, they say this is a security breach and have scheduled a meeting with HR

Hey, I work as a platform engineer for a fairly big MSP, part of my role and contract includes out of hours work on an on call rota, and our rota scheduling has been taken over by an offshore manager who doesnt seem to understand or run things by us before scheduling things in. I was on leave last week, but they scheduled my on call during the week without asking me.

My work phone is set to divert to my personal mobile, so if I'm not at my desk I can still take calls without having to carry 2 phones around with me, and I'd forgot to turn it off while off so while I was out of the room my phone got a call and someone from our (offshore) helpdesk called and my wife answered, where they told her there was a critical issue (they didnt actually ask her for a name, they just said "Hi this is XXX from XXXX, we have an ISSUE" and they needed me to work on it. My wife got a bit annoyed and yelled at them for ringing when I was on holiday and not to ring again (I know because I've been played the recording from the account manager) and then told me they rang but were reminded I was off and not to worry.

I turned the divert off on my phone and thought nothing of it, however on Monday I was dragged before my line manager and the account manager for the customer in question and asked why I didnt pick up. I told them I was on leave... I was reminded I was on the rota. I told them that I shouldn't have been rota'd for the days I was off, and that nobody had informed me...

It was a very heated conversation, during which I asked what had happened and the transcript was played back to me, and then I've been told this got serious because the issue went on so long that the customer have charged our company service penalties due to delayed fix time. I have a meeting scheduled with HR + my management tommorrow.... how bad of a position am I in?