Prescribed debt harassment

These people have been harassing me to pay a prescribed debts of over 2years being prescribed and it's annoying. I'm looking to a legal advice to stop these people from harassing me as we speak. Below is one of many sms they sent even after I've asked them to stop if they can't prove that i owe telkom money: Dear Telkom Customer kindly note that payment for your mobile service account is overdue. Please ensure payment for month of JANUARY 2025 is made to avoid adverse effects on your credit record & the suspension of your Telkom service. Ignore SMS if paid. Alternatively contact Bham&Dahya Attorneys on *** ,Ref: TELNA/***

Instead they asked me to provide them with my I.D no. but they manage to have a ref: