bad service

i have been with assupol for 1 year 2 month been paying without any deafauld or dispute just last month a cnheged banks i went to one of their brances in newtown to update new banking details .but on the 25th they went back to my previous account to try and debit they kepy going in and out adding fees on my account now they sending me threatinhg emails and sms saying if i dont pay my account asap my account wil elpase i send them emails they dont not reply..i anm so dissapointed even thinking of getting a new insurance i feel like i wasted my 14 month with them and i also feel like they dont value me as their client been calling them they takke me to pilllar and post they not willing to assist