Cell C only care about money not customers

On 3rd August 2019 Rose Martha Mahlangu bought a contract cellphone, a Hauwei P20 lite for Sbusiso Mahlangu (my son) at Wi Connect at Kwagga Mall at Kwaggafontein, Mpumalanga. She was paying R250.00 per month. Because of the COVID-19, my sister Rose was not able to pay the instalment and Cell C end up closing the phone and blocked it. Cell C contacted my sister Rose everyday requesting the payment of the phone. Cell C requested the settlement payment of R4900.00 from my sister (Rose) and they promise that they will unblock the phone immediately. On 20th September 2020,Rose did make a full payment and send a proof of payment to Cell C but the phone was never open or unblocked. She did tried several times to contact Cell C and emailed proof of payment but no one assisted her. She found that even Wi Connect at kwagga Mall is closed and so she can't go back to lay a complaint. My son Sbusiso is struggling to do his university studies because he was using the phone to connect to internet. I went Middelburg Mall Cell C, Mpumalanga. I spoke with the manager and explained to him my problem. I have emailed the proof of payment to him. He said, he forwarded my complaint to the relevant department at Cell C. They send a form so that Sbusiso call fill it and send it back to them. They promised me that phone will be unblocked soon. After few days they send an SMS that the phone is unblocked but until now my son is still struggling to use the phone. No one at Cell C is bothering to contact my sister to resolve this matter. Cell C did received the full payment but my son is crying to me everyday. Cell C was calling my sister everyday asking for payment but after the payment was made no one cares now. I am very much disappointed about the service we did experience at Cell C. If you do not want to have a headache like my family did, please avoid Cell C.