I am not an attorney, so this response focusses on principles, not the particulars of the laws and judicial standards where you do business.
Contracts are governed by state law and enforced in state courts. That includes signature cards (the portion of your deposit service agreement that specifies what token(s) must be presented before your company will perform the actions stated in your full service agreement for deposit accounts.)
A signature...any type of signature...is evidence of one or both of the following:
1. agreement to be bound by the terms of a contract with another person
2. acknowledgement of receipt of something (usually a document) from the other person
You would not be in court seeking a judgement unless one person believes the other has failed to live up to his/her obligations under the contract. The court will decide:
1. exactly what the contract does and does not require of each party,
2. whether or not each party has agreed to those terms, and
3. whether one or both parties have defaulted on their agreements.
Both your state's UETA (Uniform Electronic Transaction Act) and the federal ESIGN act tell the courts that they may not categorically disregard electronic signatures. Unfortunately, neither UETAs nor ESIGN define what is or is not an electronic signature or tell the courts how they are to determine the validity of an electronic token. Unlike ink on paper, the reliability of the technology underlying an electronic signature must be proven by the plaintiff. After you cross this first hurdle, you must then prove that the other person (the customer) agreed to use this technology to establish binding agreements. Finally, you must show that the token presented at the time of specific transactions under your overall service agreement is identical to the token agreed at the outset of your relationship.
Your company's attorney will determine what evidence you will need to provide the court in order to obtain favorable judgements...and it is your attorney who should be advising you now.