The most common Hills spare parts are available through the online store at https://hillsparts.com.au/
If your Hills clothesline was purchased in Bunnings after 2019, then they will also hold spare parts for it. These are listed on their website and can be ordered online or in store.
If the part you are after is not listed or you are unsure of the compatibility of your Hills product it's best to send some photos through to our Hills customer experience team who can help.