Camera

I am not a computer expert.  Also I do not use Zoom as a host.. as in I do not start meetings and so on. I am only on here when  my Doctor wants to talk to me.  My camera is messing up.  It flickers, changes different colors and goes in and out.  I can not ask for help from support without upgrading.  I do not want to do that since I am only on here maybe 3 to 4 times a year if that.  How can I fix my problem.  Again I am not a computer expert.  My camera was working fine.. now it is not.  It has caused me to miss two Doctor appointments  over a six month period.   Which I had to pay a fine on.  Please can you help me.. since Zoom support will not.. since they want me to upgrade my membership. Which will be a waste of my money (sorry to say that).  I am on disability and can not afford it, plus as I said I only use zoom 3 or 4 times a year. Thank you .