They demanding 2 pay...

They demanding 2 payments in short term, I received rain router on the 27th May,my payment arrangement was to pay on the 15th of June, but they loaded debit order for the first of June,but they didn't get that money now they are saying I must pay this one that is due and the one of 15th, I can't pay for router for 5 days and in two weeks another payment, this it's not fair at all