Customised Invoices

Good day 

I urgently need assistance with customisation of Invoices for one of my clients. 

My client has a contract with Shoprite Checkers, and they require certain details to be on the invoices.  Thus far they have been using excel and just to catch up (I've taken over about a year ago) and put everything online I've just worked with the current lay-out as is.

I have downloaded "Accounting Custom Layout Designer" and did design the layout and followed the steps to import the layout (yes, I did import it on my client's profile) and change it, however, it doesn't show when I want to create a new invoice.

I don't know if I did something wrong on the customisation or what the issue can be.

Please, can someone contact me to assist me with this issue, I'll pay just to get it to work.

I've tried support, and they have also just given me the steps to follow, which I have been doing. 

Thanks