Fees deducted twice for phone returned to Vodacom

I've taken a contract out on a coral blue samsung s9 but decided that I rather want a purple one RAM came and took the coral blue phone back but I was billed by Vodacom for both phones in July and they deducted R317 twice for activation of both phones. If I owe them money they can't wait to phone you to demand payment so I want to demand payback to my account for this mistake Vodacom made.