Sounds like they did change it
To refill the head that came with mine, you had to pop off the housing, wedge two separate lines into two plastic holes on the spool that wore out way too fast, carefully wrap the line, curse profusely when the line turned into a birdsnest, gently coax the two lines out the opposing holes, hold your breath as you put the spool back into the body, curse some more when the lines go everywhere, and then finally half an hour later you might be ready to start trimming again