Unhappy with their service

I am unhappy , PayJustNow agents don’t answer my calls , resorted to live chat not getting assured also been sending emails without response , worse they partnered with Shoprite MMA but they failing to confirm my voucher with Shoprite which is just a simple instead they declined saying they cannot approve the voucher that time I have paid about 2 installments and I cannot use the voucher due to them not doing their work