I contacted mailchimp support because I have an issue with 'best sellers' pulling through sold out items - they told me its due to a duplicate store but theyre unable to delete it and have offered the advice below.
Issue of duplicate stores in your account. The work around for the issue would be to use the API playground or a REST client to delete the duplicate store in the account. Before doing this, we want to stress that this deletion can not be undone and could potentially affect the sending of ecommerce automations/emails that you have in the account. That being said, I am aware that your account was running into issues with accessing the playground earlier. If you would like to delete the duplicate store from the account, we'd recommend using the DELETE call for the duplicate store through a REST client and would recommend doing this with the assistance of a developer if needed. The endpoint that you'll want to use to delete that store from the account is as follows: http://developer.mailchimp.com/documentation/mailchimp/reference/ecommerce/stores/#delete-delete_ecommerce_stores_store_id
If you would like to use the work around of deleting the store from the account using the API, we'd recommend recreating the ecommerce automations in your account to make sure that they are using the most current and only instance of the store connected to MailChimp. While the issue of having duplicate stores is unfortunate enough, I do see how not being able to access the playground and having to use a REST client/outside application only complicates the resolution to this issue.
From the answers they provided me with I can't figure out how to do it, I appreciate your help.
I was able to delete that extra store using Postman api client
Example displayed in mail chimp doc
curl --request DELETE \
--url 'https://usX.api.mailchimp.com/3.0/ecommerce/stores/MC002' \
--user 'anystring:apikey' \
--include
You can use this medium tutorial if you are new to postman and mail chimp api.