Why are my bank balance and quickbooks profit/loss detail balance?

My bank statement shows a Business Checking Balance of 30,000. My quickbooks balance shows 107,000. The numbers are different than those but the idea is the same. Why is there a huge disparity in the two balances? I am unable to sync the Quickbooks with the bank as it only leads me to the bank website. I... show more My bank statement shows a Business Checking Balance of 30,000.
My quickbooks balance shows 107,000.
The numbers are different than those but the idea is the same.
Why is there a huge disparity in the two balances?

I am unable to sync the Quickbooks with the bank as it only leads me to the bank website.

I am using Quickbooks 2011.

Will I be able to delete my banking information and put it in again to fix it or am I creating a bigger problem?

I have also noticed that changing it from accrual to cash basis does not change anything. My profit is correct but the expenses are way off.

Please help
Update: What is meant by "credit sales"?

For the most part, the information is correct but quickbooks seem to be missing stuff from the first half of the year

The expenses are the problem here, along with the acrual/cash basis not working as expected.
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