Help: trouble dropping master key

It could be trivial question.

I have trouble dropping master key. when i execute the following query..

open master key decryption by password = 'pass1234$'

alter master key drop encryption by password = 'pass1234$'

close master key

drop master key

go

I get the following result..

Msg 15558, Level 16, State 1, Line 3

Cannot drop encryption by password '********'.

Msg 15580, Level 16, State 1, Line 5

Cannot drop master key because certificate 'BackofficeServiceAccount' is encrypted by it.

But 'BackofficeServiceAccount' was already dropped.

Can any one help me how to drop master key?

I appreciate any input..

regards...

I realized the script was creating login and certificate with the same name.

Dropping the certificate first, helped dropping the master key...