You should contact our phone team and they can help you with this double charge. 

Here’s how to reach us: https://turbotax.community.intuit.ca/replies/3152013

please help, my credit card (walmart) was charged twice for the tax service under my name, made on may 11, 2020.  i just need a refund. thank you.

For refunds please contact our customer service

https://turbotax.community.intuit.ca/community/product-information/help/contact-us/00/873707