Hey, I recently went overdrawn on my bank account only £5 and my bank charged me a ridiculous fee so i decided i wouldn't pay it i didn't even realise i was overdrawn until my bank statement came at end of month and they had already charged me for it so i could'nt even pay the original £5 back now the fee has been building every month n my bank has now handed it over to a debt collecting agency

what are the steps debt collectors take to getting money back?
I don't have any sort of income at the moment either