What Happens When a Customer Has Insufficient Card Funds?

Carolina Villatoro Updated by Carolina Villatoro

Campus card/Payroll Deduct transactions work differently than traditional credit card payments. This article explains what happens when a student has limited or insufficient funds on their campus card and how Byte kiosks handle these scenarios.

Short Answer

A student/employee must have sufficient funds available on their card at the time of purchase to successfully complete a transaction.

Byte kiosks perform a balance check (preauthorization) before unlocking the door, but the final transaction amount is determined after the student selects items and closes the door. Then, the transaction will complete the processing cycle, which can take around 1-2 hours.

If the final purchase exceeds the student’s available balance, the transaction may be declined.

How Campus Card/Payroll Deduct Transactions Work

When a student/employee uses a card at a Byte kiosk, the following steps occur:

  1. Card Tap/Swipe
    The customer presents their card (tap, swipe, or scan depending on the reader type).
  2. Balance Check (Preauthorization)
    The kiosk checks whether the card has at least the configured minimum/preauthorization amount available.
  3. Door Unlocks
    If the balance meets the preauthorization requirement, the door unlocks and the customer may select items.
  4. Item Selection
    The customer removes products from the kiosk.
  5. Transaction Processing
    After the door closes, the final transaction total is sent to the campus card provider (e.g., Transact or CBORD) for processing.
    This processing cycle can take approximately 1–2 hours to fully complete.
What Happens if Funds Are Insufficient?

Scenario 1: Customer Has Enough Funds to Pass Preauthorization

  • The door unlocks.
  • If the student selects items within their available balance, the transaction completes successfully.
  • If the student selects items exceeding their available balance, the transaction may be declined.

In most cases:

  • The card payment provider returns a failed transaction
  • No funds are collected from the cardholder

Note: Some campus card systems may be configured to automatically collect the remaining available balance after a failed transaction, but this behavior is campus-specific and not enabled by default. Byte does not control this configuration.

Scenario 2: Customer Does Not Have Enough Funds to Pass Preauthorization

  • The door does not unlock.
  • The student is prompted to use another payment method (if available).

Important Notes

  • Byte kiosks do not allow negative balances.
  • Negative balances (credit accounts) may be supported only if explicitly enabled by the campus card provider.
  • Partial charges are not applied by Byte.
  • Final transaction approval, declines, and balance enforcement are determined by the campus card provider, not Byte.

Multiple Plans or Tenders (Dining Dollars, Flex, Meal Plans)

If a student card supports multiple tenders:

  • The campus card system checks balances in a predefined order set by the institution.
  • The system attempts the charge against the first tender with a non-zero balance.
  • If that tender lacks sufficient funds, the transaction may be denied — even if another tender later in the order has enough balance.

Because of this, proper tender priority configuration is important to avoid unnecessary declines.

Why Preauthorization Amount Matters

The preauthorization amount helps reduce declined transactions.

Best practice: Set the preauthorization amount close to the highest-priced item in the store.

This helps ensure customers have enough funds to complete a typical purchase once the door unlocks.

Does Byte Control Balance Rules?

No. Balance checks, tender priority, approvals, declines, partial collection behavior, and negative balance rules are all controlled by the campus card provider (such as CBORD, Transact, etc).

Byte kiosks follow the responses and rules enforced by the campus card system.

Key Takeaways

  • Students must have sufficient funds to complete a purchase.
  • Passing preauthorization does not guarantee final approval if additional items are taken.
  • Declined transactions typically do not result in charges.
  • Campus card configuration (preauthorization amount, tender order, negative balance rules) plays a major role in transaction outcomes.

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