Bio metrics letter help

[sunflower123]

Hi All,
I recently received a letter from HO asking to do my bio metrics at Post Office.This is for my extension of my spouse visa.There was also a green stamp attached with the letter that you can attach to the letter with the reference number of my case on it.At the top of the green stamp it says"affix postal stamp here".I went to Post office and enrolled my bio metrics,paid the Post office fee and received a receipt from PO that it was done.When I gave them that green sticker with reference number they informed me that they don't need it and that all bio metrics information was electronically submitted to HO and that they don' know what that sticker is for.Lady in post office advised to read the letter and see if HO requested any other documents to be sent to them.I read the letter few times and my partner as well and they did not ask for anything else apart from Bio metrics. Can anybody advise what that green sticker is for ?Did I submit my bio metrics correctly or did I need to send anything to HO by post?
Thanks

[sunflower123]

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[CR001]

Nothing you need to send. Biometrics are sent electronically to HO by the post office.