Excel Masters,
I can't get my choose formula to work

=A2*(CHOOSE(INDEX(MATCH(B2,period,0),1),52,26,12,2 ))

Essentially doing up a home budgeting sheet that i can modify at some point.

what am I trying to achieve?

A2 is a payment amount

B2 is a drop down list of payment frequencies ie week, fortnight, month, bi-annual. This cell has the defined name of "period"

I did read on another forum that the INDEX function is not needed, however, this is how it stands at the moment. At this point, it will only calculate weekly no matter what period I choose from the drop down.....
Any suggestions?