Very bad customer service

If the account is in your name then just contact customer service - no use posting here. If it's in someone else's name you have no right to cancel.

Since account is in colleague's name, get in touch with colleague and have them cancel.  If they refuse, contact your bank.

If you PAID FOR a plan belonging to a colleague, you need to get the colleague to cancel it. Regular retail licenses have no owner but the registered user, and businesses have no rights to see invoices, cancel or transfer them, even if the colleague leaves. It is very much not recommended to provide a card to someone else's retail account. Adobe offer team or enterprise plans for business.

I'm sorry to hear about your experience. Our support team was most likely unable to find an associated membership with your email address.

You should be able to cancel you individual plans yourself. See: https://helpx.adobe.com/manage-account/using/cancel-subscription.html

However, if it's your colleague who is actually the subscriber with your card details on file, you'll need them to go in to their account and cancel. Or change the payment details with their own. https://helpx.adobe.com/manage-account/using/update-billing-information.html