You probably have the spring in backwards.
Sometimes it is better - not to break down a weapon for cleaning - when you don't know what to do, other than a quick wipe with oil, nothing more should have been done anyways.
Take it to a gunsmith and have it repaired.
Usually too much spring tension is what causes a box magazine to not feed properly.
People trying to put one extra shell in the magazine.
Or other dumb mistakes that people make - such as putting a shell in backwards.
Don't laugh, I did it once - with a 7mm Remington Magnum - in the dark on the opening day of deer season once and had to drive 5 miles back home to disassemble the rifle - so I could go hunting.
The only way anything gets bent or broke is if it was misused in the first place.