And there is your problem.

If you call a plumber, and ask him to video a line, he will oblige.

You should have asked him to CLEAR the line.

But, first you tried to save some money doing something you know
absolutely nothing about (but hey - how hard could it be? It's just
plumbing right? Anybody with an asscrack can do plumbing!)

And in the course of all this, you burned yourself with nasty
chemicals, wasted hours if not days pulling fixtures that did not need
to be pulled (A plumber uses this strange device built into your system
- it's called a CLEAN OUT), and then spent who knows how much to pay
somebody to do something that wasn't needed.

And so now, because you didn't know what the hell you were doing, or
what needed to be done, and so got burned again - you have resolved to
NEVER call a plumber again.

That's clever.