Can I have two customers using the same Direct Debit Mandate ? They are two companies within a main company that use the same bank account.

I can route you to the right support, steve43.

Cases like this, you'll need to contact GoCardless Support Team. Any questions or issues will be handled better by their technical support. They can also provide you more details if it's possible to set up two customers with the same Direct Debit Mandates.

For more details about managing mandates within GoCardless, you can check out this article: Manage mandates within GoCardless.

I found a helpful article for more details about GoCardless for QuickBooks: GoCardless Welcome Guide.

You can always visit the Community if you need anything else.