Client meeting: Feeling uncomfortable, giving in, feeling regret

Hello Coaches, I had a meeting with a client this morning and the client was frustrated. He was frustrated about a work that my colleague had been postponing and hasn’t been delivering. Since I’m not his boss nor his subordinate, the conversation was irrelevant for me.

Still, because I tend to follow through with my work and stick to the schedule, I’m a team member, plus it’s probably easier for him to consult with me, the client was speaking to me as if I was the colleague. I felt super uncomfortable.

This happens from time to time, where I was asked about some work that hasn’t been taken care of (it falls in the crack and no one knows who is responsible for it) I would feel uncomfortable and would give in. I’d take on the work for my colleague. After the meeting ends, I immediately regret why I didn’t stand up for myself and I have shame.

I was thinking of doing models on them, but I didn’t know where to start. Please advise!