Smallpdf Cancellation Issue

I subscribed to the Smallpdf Pro trial on 22 April and cancelled it on the same day. After cancelling, the system showed a message that I could continue using the service until the end of the subscription, which was stated as 22 April, so I assumed this referred to the end of the trial period and that no payment would be taken afterwards. Despite this, on 22 April, my credit card in Canada was charged $144 for a one‑year Pro subscription. I only used the service during what I believed to be the trial period. When I contacted Smallpdf customer support, they told me that my subscription had not been cancelled and that, according to their terms and conditions, once it auto‑renews, it can only be cancelled at the end of the new billing period. For this reason, they refused to refund the amount. I believe this situation is unfair and misleading, because I cancelled on the same day I started the trial and relied on the on‑screen information that I would keep access only until the end of the trial. I am requesting a full refund of the $144 charged to my credit card, or at the very least a refund for the remaining 11 months of the subscription that I do not wish to use and did not intend to purchase.