The honeymoon is over between Goldman Sachs and Apple, with the former ready to dump the Apple Card as soon as possible.

Apple partnered with Goldman when it launched its Apple Card. The card has been wildly popular, especially among Apple users, but Goldman has had enough being the financial firm behind it.

According to The Wall Street Journal, Goldman executives are lamenting ever getting involved with Apple to back the credit card.

“We should have never done this f—ing thing,” one Goldman partner told colleagues.

WSJ reports that part of the friction involves Apple’s unique way of billing customers:

Privately, some Goldman executives blame Apple. Most card programs send out cardholders’ bills on a rolling basis throughout the month. Apple cardholders get their bill at the beginning of each month. That means Goldman customer-service employees get flooded early every month, making it hard for them to keep up.

So far, it appears Goldman has been unsuccessful convincing Apple to change its approach.

To make matters worse, despite disliking, WSJ reports that some Goldman execs are concerned the bank could become dependent on the partnership with Apple as a result of the high amount of savings customers have deposited into the Apple Savings accounts.

Overall, the entire Apple-Goldman relationship illustrates the challenges involved when Apple ventures into new markets. The company has a long history of blazing its own path in every aspect of its business, from the features it offers to the customer experience it provides. This can be a liberating or frustrating experience for partners, depending on their flexibility and willingness to do things ‘the Apple way.’