If there is no basis for this reversal, and it is contrary to your contract, AND, Intuit doesn't correct this eggregious action, you will have the option of suing Intiut for its breach of contract. Clearly the $1599 fee, as well as the $55000 money it took from Client and didn't send to you. That latter aspect will not be payable if in face it shows up in Client's account or Client receives a check refund. If that happens, then client needs to pay its bill expeditiously.
You can likely add the interest lost on the $55k to the extent it isn't available based on the days of when it should have been in your account, but wasn't and wasn't re-payable by the Client after it receives its money back.
I wonder if you'd be better off using PayPal? I am sure it is extremely upsetting to be shorted that cash flow of your earned income paid by the customer.
Before filing suit, you willl want to read the find print in your contract with Intuit - to make sure there is not some fine print of a term that you were unaware of, but that could validate the reversal. I am presuming that Intuit really is putting it back into Client's account, off course. Because if it does not, the client needs to jump on board, perhaps not just being a co-plaintiff in your case, but possibly conferring with the DA for theft of funds. Again, being Intuit, I'd be surprised if this were not a major error or a result of a specific term, but it must return client's money, if that is the case, either way. And if the former is accurate (major error), you can sue if they don't reimburse you your fee and your interest.
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