Why involve the telephone?
So, does your reply reach them? Who knows. Now you have to set yourself a reminder to follow up and make sure the request got through.
Alternatively, you hunt down their support email but you still need to follow up.
Then there are the rare times a company fights you on it. Then you have a whole back and forth before they finally capitulate.
I personally go through the hassle but I can understand why OP wouldn't want to.
Your Twiddla Bill for April 4, 2019 to May 4, 2019
Hey, we wanted to let you know that on May 4, 2019 we charged your credit card $14.00 for your monthly Twiddla Pro subscription.
You can find additional information regarding your bill, individual charges, and your account history by logging into your your account at https://www.twiddla.com/ and navigating to your "My Account" page. You can also make changes to your subscription or cancel it altogether from that page.
If you have any questions regarding this charge, or would like to yell at us until we refund it, please contact us at info@twiddla.com.
Thanks for the business!
Jason Kester
info@twiddla.com
For better or worse, the chargeback is the only weapon end-users have anymore.