Lying agents on chats

Im am Beyond frustrated with them right now. We cancelled our openserve Fibre with them as we had it installed as a fail over but used it once. Sent Back the routers as per their policy. We were billed full for the router anyway which is ok as the courier company lost the package and found it later than web africas 21 day policy. For the last month i have been battling to get a credit on this account. The amount of time i have spent on whatsapp with their agents is insane and calling them gets you nowhere as there is no answer. I have spoken to multiple agents on this chats where all of them confirms the receiving of the router and promises the credit will reflect in 24 hours or they will get back to me and none of this happens.

I have other service's with them and im happy with that but getting this credit passed on my account is like giving birth al over again.