******** cellphone return policy

Bought a phone at Truworths on 05/10/2022 on account, it was a RedMi 128gb R4000. The phone was so slow, takes the whole day to charge and started having alerts of overheating and storage issues within 3 days of buying. I took phone back today the 12/10/22 and Truworths refuses to exchange apparently their cell phone return policy is to send the phone to MTN and I have to wait 30 days to find out if am gonna be refunded. How can this be when consumer law says if the cellphone is returned within 7 days you're entitled to a full refund. Now how am I to sit 30 days without a phone?