Huggies Nappy Pants Voucher useless if no stock in stores

Huggies promoted a R30 voucher for their new Huggies Pants that was due to come out in September 2018. The voucher was received late September and valid for 30 days. After not being able to find the new pants in the correct size in any stores near me within the 30 days period, and being informed by Checkers that there is a problem with stock from the supplier, I wrote to Huggies letting them know the issue and asked to have a new voucher issued. I didn't get a response. Wrote a following up email and got no response. Considering all the Huggies nappies I have bought so far, this is a very sad way to be treated as a loyal purchaser.