Bad Product an only wnat to give R100 voucher

I bought a jumbo Pack of Pampers nappies and the pack was damage product was leaking and did not absorb the urine as usual. they sent me a R100 voucher which I need to drive R100 petrol out to collect but I did not collect it, cause I stay on smallholding far from town. I asked them for a replacement pack last week and no reply ever since. I am not happy with the R100 voucher. and want a replacement pack delivered to my work address. this is going on for about a month. my friend had a complain about another product baby related stuff and she got hers within two weeks. why do I need to wait longer than a month to have this sorted.