Terrible company

Throughout my duration with this company it has been unpleasant, In November 2019 i reversed my debit order because i was loaded with 20+20 data and not the 40+40 data i am paying for, i have sent numerous emails and get one call where the person does not understand my point of receiving less data, then in Dec19 I received 20 + 20 data again, but my account was debited for the full 40 + 40 price. Now in Jan20 my account has been debited and i I have not been loaded with data as they are saying my account is in arrears and i need to pay in order to get data, however do you not get it, for the last 2 months i have only been loaded with 20 +20 data and not 40 + 40. Someone called me and explained they no longer roll over data and the will only top up with the difference however yet again topping me up with 20 + 20 and with the existing data i had does not equal to the 40 + 40 i am paying for, please cancel my contract i do not want to be part of this anymore. My contract ends in March 20 and i thought i would stick it out however how can one do so when you no not get what you are paying for, this is also not the first time i am experiencing this, i have had this problem before and even went to their offices and totally ***********