GI posted in wrong month via COGI (issue in MB5B)

Dear experts,

I face a strange issue. Hopefully you can help me.

Originally this problem comes from PP orders. Due to some issues (date of manufacturing was missing) some GI for consumption have not been issued.

All these GI came into COGI.

The confirmation of the PP order (using CORK) has been done by 31.03.2016.

Somehow the GI of the consumption has been done with COGI but the posting date was 01.04.2016 instead of 31.03.2016. 😕

Result is now that the material document 4900515900 will be counted for April instead of March in TCode MB5B.

As you can see there were many tries to cancel the confirmation of PP order and confirm again but always 31.03.2016 has been taken as posting date.

Regrettable I cannot cancle material doc 4900515900 using MIGO or MBST as I need to cancle it over CORS (cancellation of PP confirmation).

Do you have an idea how to manage the cancellation of material doc 4900515900 for 01.04.2016 posting date that it can be posted for 31.03.2016 again?

Many thanks in advance

Best regards

Patrick