Lack of Service

On 28 February 2020 I phoned and sent an email disputing an account and was promised a response "within two working days". I have sent several follow up emails, and as at today 4 May, 2020 I have received NO FEEDBACK other than their automated response. I have been paying all accounts OTHER THAN THE AMOUNT IN DISPUTE, Today, I received an SMS from them threatening to cut off my electricity supply. It appears that my query is in the "too difficult to resolve" file, and now they are resorting to bully tactics even in these lockdown times where many people's income has been severely curtailed. The lack of response should not be blamed on the lockdown, as my query was sent way before that commenced.