request a cancellation of the purchase

Hello.
Nextier, a software distribution company.

We bought Redmine through the distributor
The client company wants to cancel the order, so we have to cancel the order.
I can't get in touch with the sales team and the support team
I'm contacting you because I have an email address on the site.
I need to request a cancellation of the purchase, how can I contact you?
Please reply.
Thank you