We're sorry to hear that! We would highly recommend reaching out to us by emailing hello@hubgem.co.uk, or contact your HubSpot Customer Success Manager to discuss your reasons and see if there is anything we can advise on to help you get more value from the tools.
If you are sure you want to cancel, you can find more information here. Note that HubSpot subscriptions are usually a minimum of 12 months commitment.