Certificate Manager does not allow me to delete an uploaded certificate because it is "in use"

Question

I implemented a API Gateway custom domain by using self-signed certificate uploaded on Certificate Manager, this was for learning purposes, once i finished i deleted both the custom domain and the api gateway, but my certificate still seems to be "in use" state, it's been more than 1 day since i deleted the associated resources and i'm still not able to delete the certificate. According to its properties the certificate is associated with three load balancers from another account (not my account ID), something like this:

arn:aws:elasticloadbalancing:us-east-1:another_Account_ID:loadbalancer/app/prod-iad-1-cdtls-1-2-104/87ea7bd28e18ef45
arn:aws:elasticloadbalancing:us-east-1:another_Account_ID::loadbalancer/app/prod-iad-1-cdtls-1-2-793/dd9eb9379f71a0ba
arn:aws:elasticloadbalancing:us-east-1:another_Account_ID::loadbalancer/app/prod-iad-1-cdtls-1-2-862/56fc8591797a2875

I suppose this configuration was automatically done by the custom domain set up, what can i do in order to finally delete the certificate from Certificate Manager?

Answer

Hello.

I think you probably have a similar problem to the question in the URL below.  
https://repost.aws/ja/questions/QUD6O2O6z2QjelpBx6bcnBaA/cannot-delete-acm-certificate-due-to-uncontrollable-resource-associations

It seems that the person asking the above URL opened a case with AWS Support under "Account and billing" and had it removed.  
Inquiries under "Account and billing" can be made free of charge.  
https://docs.aws.amazon.com/awssupport/latest/user/case-management.html

Certificate Manager does not allow me to delete an uploaded certificate because it is "in use"

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