Absolutely no customer service

When i opened my account at Truworths i explained to them i receive my income the tenth of each month and i received a message that is no problem, following purchases i always paid more than the installment on my income receiving date ,four months later i received a message I'm listed as a slow payer at credit bureau and upon contacting them I've been informed they will not change my statement date and either clise the account or have a record at the credit bureau and there is no way to contact top management