How do I remove the Agitator from a Simplicity SEW3220 Washer?

We have an iPod headphone wrapped around the agitator and can't get it out. How do we get the agitator off so we can remove the wire.

I can't find any information on Simplicity. It seems it's a semi commercial brand of Danby. Works really well though, other than this user problem of ours. We've had it since 1996 trouble free after buying it new from a repair guy we can't find anymore.