Use invoices and written agreements that specify when payment is due. Send a reminder before or just after the due date, then document any arrangement. Do not add fees or interest unless the terms and applicable law support them.

Make the due date, any grace period, reminder sequence, late charge if lawful, and process for disputed invoices explicit before accepting work. Use a consistent, respectful reminder and pause added charges while a genuine billing error is reviewed. Check contract and consumer rules that apply to your service. Do not add a late fee retroactively or describe an estimate as a confirmed invoice.

Apply any disclosed late charge only after checking that it is permitted for the agreement and service.

Send reminders to the billing contact named in the agreement and include a copy of the invoice. Keep any fee separate from the original amount and explain how it was calculated. Do not use threats or add a charge that was not disclosed or is not permitted.

Ask a lawyer or accountant about terms for your business. Keep your public service offer separate from payment enforcement; create a KobStore page and provide written terms to each client.