is there no way possible whatsoever for the customer to get back their money?
No. Scammers have permission from the judge to continue using depositors' funds to run their operations. Their strategy is to milk most money as possible paying their own wages as company's employees, so once the deadline for the recovery is over, there will be only pennies left for creditors. If the judge had decided the opposite then it would have been possible to retrieve funds partially. But that is not the case, so next time better to avoid these platforms.
The users of those platforms really need to read what kind of terms they are accepting when they sign up to them, they basically gave their funds away to Celsius and while it is completely unfair, the law only cares about what is legal and not about the unfairness of the situation, and I hope anyone which has not suffered because of something similar looks at this example and learns from it, as this is much cheaper than the alternative.
And that is not an exclusivity of Celsius. Any crypto lending platform or exchange going bankrupt would lead investors and customers (unsecured creditors) to the same infamous fate. There isn't any insurance program which covers users from crypto platforms in case of bankruptcies, with the exception of Nexo, maybe, which claims to be insured up to 250$ million dollars.
However, before this scandal I thought these platforms were safe to invest, since they are regulated businesses, therefore the justice would stay by the side of the victims. After all, it's also a good lesson that we shouldn't act expecting the law forces are going to save our skin in case something goes wrong. In fact, it's more likely the opposite happens.