The short answer is they can. According to the Local Government: Municipal Systems Act 32 of 2000 municipalities have the power to charge interest on municipal accounts in arrears over residential properties. The Local Government: Municipal Property Rates Act 6 of 2004 does require a municipality to provide you with a written account of your rates and taxes, but further provides that you will be held liable for payment of your rates and taxes regardless of whether you received the written account from the municipality or not. It is assumed that it is common to expect that your municipal rates and taxes will be due from time to time and non receipt of a municipal account cannot therefore be used to avoid liability.
This means that you cannot be exempted from paying arrear rates and taxes, including interest thereon, purely based on non-receipt of the written account from the municipality. It remains your responsibility as owner to do all the necessary and obtain the necessary information from the municipality if you do not receive regular accounts and stay up to date with your account. However, should you dispute the account or interest charged if may be useful to engage the assistance of your attorney to liaise with the municipality and help ensure that your account has been correctly charged.
Go to the municipality and make the necessary enquiry in the event that you do not receive a written account. Your enquiry must be made in writing. You can either send an e-mail to the relevant department at the municipality or go to the municipality with a letter of request.