They could claim they never received it; if you do a lot of business on Venmo, it might be worth investing a few bucks in sending via certified mail.
I don't think they'd have a leg to stand on in claiming that your version of the form was incorrectly rendered, as long as you provided all the requested information.
If you failed to include every piece of information the form asks for, perhaps they'd have an argument to reject your opt-out; the contract does specifically say that every piece of info must be included and it must be signed.
No click to confirm, Venmo has to mail YOU to ask for binding arbitration by certified mail, asking YOU with a SASE to confirm by certified mail back. Then it would be consent.
I don't think they'd have a leg to stand on in claiming that your version of the form was incorrectly rendered, as long as you provided all the requested information.
If you failed to include every piece of information the form asks for, perhaps they'd have an argument to reject your opt-out; the contract does specifically say that every piece of info must be included and it must be signed.