The goal
When a customer disputes a card payment, their bank raises a chargeback and Paystack has a short window to respond with the merchant’s evidence. Banks send these in bulk files. Handling them meant hopping between a VPN, an old chargebacks tool, Zendesk, Google Sheets, Slack and Watchtower. As volumes grew, so did the chance of a human or tooling error, and every error could cost money.
Where Paystack fits
A chargeback starts with the cardholder’s issuing bank, which raises a claim with the acquiring bank through tools like MCOM and VROL. The acquiring bank then raises it with Paystack, mostly over Excel files and email. That last hand-off is the part Paystack can improve without much friction, so that is where we focused.
01 · Research
Process
I spent time chatting with and shadowing the operations team as they logged and answered real bulk files, noting every tool, hand-off and workaround. We then mapped the full journey on one board, from the moment a bank or card scheme raises a dispute to the moment a response goes back.
The journey
Disputes move between Paystack, merchants, acquiring banks and issuing banks. We mapped each route step by step, with who is involved, the tools they use, and the challenges and open questions at each stage.
Route 01 · Accepted
Disputes team · Issuing bank · Merchant
Keeping track of requests is tedious, and communication gets drowned in the inbox.
How it works
Challenges and open questions
Route 02 · Declined
Disputes team · Merchant · Issuing bank
The bank is typically looking for a reason the customer is right, so the evidence has to be compelling.
How it works
Challenges and open questions
Route 03 · Pre-arbitration
Issuing bank · Paystack · Merchant
There’s no resolution timeline, so banks can come back months later with a pre-arbitration claim.
How it works
Challenges and open questions
Route 04 · Fraud
Disputes team · Issuing bank · Merchant
Banks sometimes send fraud claims in bulk through the wrong channel, which makes them hard to handle.
How it works
Challenges and open questions
02 · Insights
What we learned
Disputes arrive through many channels and pass through at least six tools before they are resolved.
Some banks email individual team members directly, so the rest of the team can’t see what has come in.
The same chargeback can be filed twice, once as regular and once as fraud.
Deciding who is liable depends on the experience of whoever picks it up, which puts money at risk.
A bulk fraud file takes about six hours to process and can’t be split between people.
Nothing tracks how long a dispute takes, so pre-arbitration claims can come back months later.
Deadlines
Merchants have just 16 hours to send their evidence before Paystack responds to the bank.
Formatting
Some banks only accept evidence as JPGs under 200KB, so PDFs had to be converted and compressed by hand.
Card schemes
Mastercard separates fraud chargebacks but Visa doesn’t, so the team sorts them by chargeback code.
Matching
Bank files rarely match Watchtower’s format, so columns are cleaned up in Sheets before every upload.
Framing the problem
What if the team could log, match, collect evidence and respond, all in one place?
The question we designed around03 · Solution
Ideation
In an ideation workshop with the disputes team, ideas clustered into three themes: automate formatting, automate evidence collection, and build one tool for the whole process. We prioritised the last, a central platform that would connect to Zendesk, the internal dashboard and partner disputes APIs, and resend pending disputes automatically.
The most impactful features were the ones that cut manual work by automating three things: matching claims to transactions, making dispute responses visible to the whole team, and generating and matching responses to declined disputes.
Flows
Uploading a bank file is one step. If it fails, DART explains why so the file can be fixed and uploaded again.
Evidence is generated, matched to the original file and sent to the bank, either through a Zendesk ticket or a bank’s own portal.
Prototype
Each bulk file becomes a batch in DART, with every dispute’s status in one table. When the team is ready, Respond to bank generates the evidence, updates the bank’s original file and sends the response, with progress shown at each step.
04 · Outcome
DART rolled out in phases through the first half of 2023, and by September the disputes team had moved onto it completely. Evidence is now formatted to each bank’s and card scheme’s rules, with PDFs merged and Paystack receipts pulled from Watchtower. Failed evidence generation can be retried, Interswitch fraud chargebacks are sorted with no manual work, and proof of authentication is shown alongside each dispute.
Success metrics we set
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