What do you do if your client wants to make you his client?

[teamandromeda]

In my 10 years of being an entrepreneur, I had a lot of times that my clients asked me to try out their service to do my work better as well. So for a restaurant I was invited to have a free menu, or a makeupbrand I got a voucher to get some beautyproducts and so on. For now I just keep my services online without try-outs within Fiverr and I'm okay with that.

With this particular client he ordered and I delivered. After delivery he asked me to expand and do more service outside of Fiverr. I said I was busy. Now he send me an invitation with a link to become his client but that is 'just a link to have an online meeting'. I'm a bit uncomfortable, I have no interest in becoming his client or having meetings outside Fiverr but I want to keep him as a returning client. What is the best way to solve this and to answer?