Pathetic service from Merchants team

I ordered things for a pet on Takealot (paid via PayJustNow), I ended up having to cancel the order before it shipped because we lost the pet. Takealot processed the refund, but when it came to PayJustNow updating my account they made one heck of a mess! The order total was R1,839.00, PayJustNow only refunded R190 off my account. The online chat portal is very unhelpful, when you phone it always just rings (no one answers even if you phone at different times during the day), and they take ages to reply to an email. I sent an email to them regarding the incorrect refund amount on 05/05/2026 (2 days after I cancelled the order). I only received a reply on 12/05/2026. I answered the lady's question via an email reply the same day. No feedback received until 19/05/2026, a day after I sent a follow-up email. The feedback was that the matter was escalated to the merchant team. No feedback or correction received to date. My next installment is due today and they are already threatening with penalty fees if it's not paid by COB today. BUT they can't fix a refund mistake THEY made since 05/05/2026 already!!!!