Rossendales say we can afford more than we can

We have received letters from Rossendales regarding council tax arrears we completed a financial statement as requested and offered an affordable amount but stated that we were unable to pay anything till the end of the month due to my partner starting a new job after being made redundant and me returning after mat leave and we didn't get paid till then. They have stated they wand over double what we have offered which we cant afford but have also stated they want payment on the 13th we have been in touch and said that we are not in a position to make any payment on that date they have stated they have noted it but still want payment on that date and have stated we can afford this. We have about £100 to live on for the rest of the month and have a 9 month old baby but they say we can afford £255 by the 13th

Rossendales say we can afford more than we can