Spam smses

I keep getting smses from ntt Isuzu ladysmith informing me of license renewals. I have already asked them to stop. I am getting regular smses informing me that random people need to renew licenses. Literally 5 smses at a time informing me that Mr or Mrs whoever needs to be reminded. Stop this now or I will report you as this is against the popia act. I have requested this to be done in the past. I don't even live in ladysmith. What the heck!!!.