Some years ago I was seeing a t for individual and then asked her for help with marital....I had two individual sessions each week, one on Monday and one on Thursday. And Wednesday we had marital sessions. I always needed to talk to her after a marital session. She was after all my therapist.
My t always returned calls. Same day or next, but never later.
I would call t again and leave a message saying I really need to talk to her before coming for another marital session. I'd mention that I'd left a message last week, asking for an individual session, and did she get my message? I'd say it's important for us to talk before having a marital session and could she give you some time over the phone or in person?

Dear, this is hard. I know. Take gentle care,