Here's one of those invoice mails in its entirety. Sent from (and reply-to) info@twiddla.com. See if you can figure out how to go about cancelling your subscription or getting a refund:
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
https://www.twiddla.com/