MTN IS OVERCHARGING FOR CALLS

I purchased 450 monthly minutes for all networks on 5 April. Made calls that didn’t come up to 15 minutes combined. My package was depleted and I was told that I purchased a 900 second daily top up which is a lie because at no point did the option I selected state that I’d be given 900 seconds daily because that’s now how their monthly voice bundles work. I was taken from pillar to post with their agents and no one assisted. In fact they want to convince me that I purchased something I didn’t. I proceeded to ask if they’re saying I bought a daily top up, why was the 900 seconds not loaded for 6 April and they have had no response . I was charged 450 minutes for phone calls that lasted 15 minutes. They refuse to reimburse me! Absolutely terrible customer service as their agents and supervisors think that “we don’t know what to tell you” is an good enough answer