Immigration legal expert need / recommendation (Zurich)

I am applying for EXTENDING my residence permit since March.
Its been a nightmare to deal with an immigration officer who goes round and round and asks the same questions again and again!

Every month, I have to reply to the officer such as the bank statements: which I have provided four times!

As I am working as a freelancer but they are all commission based jobs. I have signed four clients and three of them are Swiss based business. Because I prefer to work for multi-projects and which I can gain more money than salaries.

Yes, I know I need to pay myself the compulsory; And the office asks me at least three times about to register as self-employed, but I asked the organisation I am not qualified to register as SELF Employed because you need three invoiced clients and got PAID!

So I go back to explain to the officer, THREE TIMES in THREE Months with Three Letters! The officer just don't get it and It drives me crazy!

I am UK Citizen and I am totally stuck in this situation so I need who understand the immigration matter to let me know how to answer to the officer.

Please note: I am applying extension not a new one!

Thanks.