Checkbox in Custom Fields Not Working

I need to create custom-fields with Checkbox so that user can choose several values to be displayed in their listing. (Example: Forms of Payment Accepted: Cash, Venmo, Paypal, Zelle, Bitcoin)

All the custom-field values are there in the backend to be selected, but ONLY the 1st checked value displays in the front end with the shortcode. The other values are not displayed in the front end at all but still remains checked in the backend.

How do I fix this?