Incorrect billing ad debiting

I purchased items in Dec 2021 and 2 months after billing me I was informed it was completely the wrong amount they debited me with and with this result my Acc fell in arrears. To date I've sent numerous emails asking to get this resolved and my amount that I owe recalculated on a new premium to get the account out arrears and my credit limit reinstated till today no help was given and now trying to pay the arrears I get smss from the collections to settle the Acc imm, o one helps and I still smed emails and ask the query to be escalated and no one helps! How is This my fault if homechoice makes a error? I need help and no one is interested and I've been a very long standing client for years with no issues on my Acc and now they do this