3ds can't read cartridges

[wasa1]

Hi, i buyed this used 3ds and a r4i gold, when they arrived the 3ds readed the r4 without any problems, now, he suddently stopped working but i don't know why, the pins of the 3ds are in perfect condition, not even a little bit of corrosion or imperfections, please help (i didn't try a different cartridge, i have only the r4)

 

[wasa1]

srry for grammatical errors

 

[wasa1]

Ok, i figured out that the problem was the cartridge, but now i have a new problem, when I insert the card, it doesn't click and doesn't stay in place