Linking payment to commercial website

I am looking for someone to help me link my commercial website to a payment option. My website is already created on Squarespace and I have purchased the domain. I also have a shopify site but highly prefer the squarespace site. My preferred payment provider is Payfast and the currency of choice is Rand. My website will have 1 to 10 products or services available for purchase. I need someone experienced in setting up this type of payment system, efficiently and securely. A good understanding of both Stripe and PayPal is also required, as I am open to other payment options. If you can help, please reach out with your work experience and a quote. Thanks!