Hey all, i tried seraching but nothing really cam up about bulb issues,

My taillight went out the other day and so i bought a replacement, and i think its too short and the connection isnt constant. Sometimes the blinker will be normal speed and sometimes(most of the time) it is rapid fire mode. I took a file and scrapped the connection to clear it up incase that was the problem, that worked for a little bit but now it seems like its bad all the time...Anyone had this befor?