Upvote:5
You have created quite a problem for yourself. In your first application your income statements differ significantly (why the amounts differ is of no concern to the inspector). The updated document you sent is apparently unreliable in your country.
Your bank statements show small balance -> big deposit -> big withdrawal. This looks a lot like money laundering or just bumping up the balance for the application. The large payment from your cousin was poorly timed.
Nigeria is pretty much top of the list where fraud, false documentation and outright lying on visa applications to the UK are concerned, and your story (which I will assume to be true) sounds just like many other stories that are not true. You cannot backtrack and try again as a changing story looks even more like fraud.
Book an in-person appointment with the visa department, bring business records, long-term bank records, phone number of your bank manager, major customer etc. etc. You need to convince the inspector of 2 things: that you can support yourself during your visit, and that you will leave when you say you will leave. Based on your application history your cousin may be visiting you instead.