OP - tough s*1t really.
Economics 101: supply and demand, if everyone wants widgets and nobody has them, expect to pay.
BOI could drop their rates to zero in the morning, but they'd be calling in your loan a week later when all their deposits walk out to KBC, Nat UK, Investec etc, and then coming looking for a bailout the following week.
Govt regulate deposit rates, all money will walk out of the banks and into state savings, if they drop those rates, they'll walk out to overseas banks.
If you feel your business qualifies as a charity, I think there are supports available. Otherwise, depositors aren't the saint vincent de paul.
Written contracts are a different matter entirely.