Echo

I joined a meeting and for the first time ever, experienced a horrible echo.  My phone was off; there were no other devices active in the room.  I tried both speaker types. I downloaded a new driver. I contacted Zoom support and the bot told me I had to pay for a plan to get to audio settings to cancel echoes.  I did notice upon leaving the meeting that somehow I was on as two participants - not sure how that happened; but could that have been the problem?