Horrible customer service

I made a subscription with the company of a galaxy A23 I think the biggest mistake I made was making the first payment on the 23 now they assume that I must make my monthly subscription on that day when I try to email them and tell them they need to change debit date to 25 they told me I must pay R300 that I didn't sign for it,what kind of company if you want to change payment date they want money I feel like that's day light ******* and they demand the money on the 23 and they always give you threats that they are coming to collect the device I'm just tired of them every month that I'm getting threads that they are coming to collect the device your service it's so horrible I won't recommend anyone to take a phone there