Multiple miss CALLS FROM MTN, NO FEEDBACK ON COMPLAINT LODGED

Mtn's service is extremely disappointing. I would never recommend them to anyone. They do not respond to complaints. They do not bother to assist their clients correctly on the phone also. I'm receiving miss calls from MTN on a daily basis, when I answer the call then drops. Al this because I'm due for an upgrade. I never showed any interest in this, but yet they are harassing me. Is this allowed with the POPI act even though I never gave them permission to contact me? Multiple miss calls on a daily. I've lodged a complaint on Hello Peter previously, but like I said, no response from MTN. Really the worst company anyone can choose to take up a contract with just because of their customer service experience