Miway incurs bank costs to Pensioners

I am a pensioner. My debit order date is 1st of a month. This month the 1st, was a public holiday. Miway chose to deduct on the 29th. THe debit ORDER bounced leaving me the bank charges. No call to me to say we doing this. Why do they not debit on the 2nd, who gave them permission to take it earlier? When i called they said, its not their problem it's the bank. I must get funds back from the bank. This is NOT the first time thus has happened, but i left it. I'm A pensioner, i cant afford these extra costs that are created by MiWay. I always make sure the funds are there, but you can't just decide to take it early and take ZERO accountability for costs incurred to me