I have a problem with my plane and I can't figure out what's causing it...

the edge of part B (the blade) is sliding back from part F every time!
I sharpened the blade
I have locked it in every way possible
I cleaned every drop of oil out of it, didn't work
I put a washer on the screw, not only that it didn't really worked, it blocked part G (the angle thing)
why is this happening?
maybe I should buy a different one?
in that case, which one? (I don't have a hugh budget)
with thanks.. MR. Dubin
Did you put the iron and capping back together the right way round.......silly question but a common fault.
strange how it is slipping. is it the capping that is moving or the iron and the capping?
the only thing that's moving when everything is intact is the blade
with thanks.. MR. Dubin
I have a bolt between the chip breaker and the blade that keeps them together at the desired spacing. I would take a picture but I took my plane apart for cleaning and cannot find the blade/chip breaker.

Also, you may want to tighten the screw that is on part C if you have not already done so.
I have it too, it's inplace and with the right spacing
C is tighten to the max
with thanks.. MR. Dubin
may not be seated properly. fit the iron and cappinig, fit the holder over the screw head and snap back small lever, if not tight lift small lever and turn screw down 2 turns and try again. if tight , wiggle the blade alignment lever below the iron to full left then full right a few times. this should seat the iron on the frog properly. turn the iron adjustment knob until the blade produdes a hair thickness. and plane away.