Heres an interesting article on the topic, from 2017.

https://www.outsidethebeltway.com/what-happens-when-a-business-wont-accept-cash-for-payment/

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Another good one, this from 2018.

https://www.expertlaw.com/library/consumer-protection/it-legal-refuse-cash-payment

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These are 5-6 years old so I don't know if there's been any changes in the legal arena that would affect cash payments.

Heres an interesting article on the topic.

https://www.outsidethebeltway.com/what-happens-when-a-business-wont-accept-cash-for-payment/