Chargeback

Hi everyone

So, I ordered £56 worth of goodies from a small business. However, when I received the box I noticed £20 worth was missing. I contacted the business owner who apologised and said they’d send me out a new batch a week later, I waited an extra week they’ve not sent anything out or replied to my emails. So, should I go through to file a chargeback as I’ve barely emailed them and kept my emails very polite and professional and I’ve kept their emails as proof so how do I go about a chargeback? If ur was £5 or even £10 worth I’d have let it go but it’s just the etiquette really of supporting a small business only for this to happen.