Missing Recording

I record meetings with clients to be transcribed. These recordings are crucial to the functioning of my business. I had a meeting last night with a client. I stopped and started it a couple of times (nothing out of the ordinary, I do that all the time), so there is a recording at 4:31 and 4:32. The one at 4:32 lasted about 6 minutes. I turned off the recording and turned it back on - my client remembers me doing this and remembers hearing the "this meeting is being recorded" message, so we know it was recording. The meeting was long, maybe an hour or so. It still has not shown up in the recordings. It is VERY important that I get this recording. Can anyone help me?