A chargeback is a customer disputing a card payment with their own bank, which reverses it.
The money goes first
The amount is withdrawn from the business at the point the dispute is raised, usually with a fee, and is returned only if the business successfully evidences the sale.
This is the reverse of an unpaid invoice, where the business at least still holds the position. Here it is already out of pocket while the argument runs.
The common reasons
The work was not as expected, which is a scope dispute.
The customer does not recognise the charge, frequently because the trading name on the statement differs from the name on the van.
Genuine card fraud.
What evidence recovers one
Signed authorisation, the signed contract or accepted quote, photographs of completed work, delivery or completion confirmation, and the record of communication.
Assembled after the dispute, this is difficult. Kept as a matter of routine on every job, it is straightforward — which is the practical argument for documenting completion.
Deadlines
Response windows are short and fixed. A missed deadline decides the dispute regardless of the merits.
Reducing them
A clear trading name on statements, so the charge is recognised.
Contact made before the payment is disputed. Most chargebacks are raised by customers who tried to resolve something and did not get a response — see complaint handling.
Documented completion as standard rather than on request.
Excessive rates
Processors monitor chargeback ratios and can raise reserves or withdraw the account above a threshold. Beyond the individual losses, that is the reason to treat the rate as a number worth watching.