Debit order dispute

If you change a bedit oder date and the next from the 1st to the 25th and the next debit oder should run on the 1st of June so this to my confirmation after I spoke to them should run on the 25th of June. Today after speaking to them they told my that no Im wrong and they have to debit my the 1st and 25th May and again on the 25th June. and advised that they will not be able to revers the debit oder for the 25th of May, If I new this when I called them and gor confirmation for the lady I spoke to I would never have change the date from the 1st of June to the 25th of June.