My account accumulate interest with 3 days

last week Friday i phoned in to asked if they received payment i made the guy said he will try and retrieve my payments and i should phone back on Monday i phoned no one answered the phone ..Tuesday 20/03/18 i phoned back spoke to Shuad he said he will contact me back he will escalate the payments that was made to accounts department as he can see it on his system that the payment were made of R600 and R300 no phone call back. 22/03/18 Wednesday i phoned in again spoke to Tashreeq i told him i waited for a phone call from shuad he now told me the balance was R2159