Missing items

Very dissapointed in delivery service of the courier guy I received my shein package with 6 missing items worth R680, Shein confirmed their warehouse packed my 20 items, I informed immediately when i received it about missing items also how package was taped after listing all.above they still got back to me saying I will not be compensated after shein said the same so what do one do from here i am so frustrated as nobody can confirm my missing items