Disappointment after disappointment

Disappointment I took up this cell c 24 month contract in May and I realize now that was my biggest mistake. I asked for the debit order date to be the 20th of each month , they debit on the 31st ( of course it will bounce) now they come back to me saying they have changed the date however I'm liable for bounced payment fees. How is it my fault you debited on the incorrect date? PLUS educate or train your staff better because whenever I inquired about the bill the line cuts and the manager never calls , utterly disgusted. Looking to cancel SOON!!!