Invoice Nightmare ethical or not

Ii am totally disappointed with the manner in which takealot has invoiced my last 2 orders. firstly my order in November-20 could not be fulfilled and i landed up with a credit of R661 (why this was no credited to my credit card is beyond me), in December-20 i purchased goods to the value R1305 less credit invoice amount reflects R664 all good so far this week i reconcile my bank statement and see there is an amount R994 deducted this is an overcharge R350 to query this is a nightmare there is no email or number one can contract at accounts, i used the general number i unfortunately did not get much help there as eventually after 20min on the phone she tells me there is another invoice for R350 from "Market Place" there is no reference or reflection of this invoice on my account.....question is how often does this happen and is this practice at all legal, to claim VAT return i need the invoice to reflect the correct amounts....definitely will not accept Credit from Takealot again i will demand the refund into the credit card account