Hi Sivra,
Please refer to the following articles to request a cloud solution provider relationship with an existing Office 365 customer:
If you have problems in doing this, I’d like to collect the Office 365 tenant information of your Office 365 organization and forward it to our related team to help you accomplish it.
To protect your privacy, I’ve sent you a private message to collect the Office 365 tenant information. Please refer to the following article to reply to it:
https://answers.microsoft.com/en-us/privatemessages/list
If anything is misunderstood, feel free to post back to correct me.
Best regards,
Mouran