Shipping Woocommerce plugin upgrade needed

Hi there! We need to upgrade the shipping plugin at: [login to view URL] ([login to view URL] Shipping API) - to calculate free shipping to all major centres in South Africa (Durban, Johannesburg, Cape Town, Bloemfontein, etc.) but outlying areas need to calculate the balance of the shipping. Ie. where the plugin currently calculates shipping all the way to the customer's door, this now needs to remove the cost of the shipping to major centres and just charge the balance of the shipping (from eg, Durban central to outlying areas). The [login to view URL] shipping plugin is open source so there is no ownership issue here. The [login to view URL] in the meta data returned the ‘regionalSurcharge’ would dictate that it is not destined for a major or main As part of this process, we'd also like to add a couple of lines of text to the customer confirmation email linking the customer to the Collivery Tracking (Waybill) screen: [login to view URL] example waybill 232323 would be replaced with the waybill number from that order.