What should Micaela's Hair Design Studio do to remedy a negative balance?

The most appropriate action for Micaela's Hair Design Studio to remedy a negative balance is to perform a top-up by adding funds from their bank. A negative balance typically occurs when the charges to a business exceed its available funds in the Stripe account. By adding funds through a top-up, the studio effectively rectifies the negative balance and ensures that they can continue processing payments and covering any upcoming charges or fees. This action restores the account to good standing, allowing the studio to operate normally without any interruptions due to lacking funds.

The other options do not directly address the issue of a negative balance. Requesting a refund from Stripe does not resolve the negative amount; it's a request that could potentially delay funds rather than add to them. Decreasing service rates may affect incoming revenue but does not provide an immediate solution to the existing negative balance. Extending payment terms for customers can delay cash flow but does not directly contribute funds to rectify the negative balance either. Thus, performing a top-up is the most direct and effective remedy for their situation.