Information: The following is information about accounts receivable.$(1)$ The credit policy of a certain company stipulates that the buyer should make payment within $15$ days after the arrival of the goods. Company A intends to purchase goods worth $2$ million yuan from the company, but due to financial constraints, payment cannot be made within half a month and needs to be delayed. After learning about this matter, the salesperson Black of the company discussed with the accountant White and decided to request a usage fee of $20000$ yuan from Company A$,$ while also helping Company A extend the payment time, ultimately resulting in long$-$term outstanding accounts receivable for the company.$(2)$ There is a $2-$year outstanding amount in the accounts receivable of a certain company. On December $25,2018,$ it was learned that the debtor has entered bankruptcy liquidation proceedings, and their bankruptcy assets can only offset employee wages. In order not to affect the profit performance of $2018,$ the company has decided not to write off this accounts receivable temporarily and will continue to keep it in its account.$(3)$ A certain company received a repayment of $100000$ yuan from Company B for previous years, as the accounts receivable have been written off. The company will issue a cash check for $100000$ yuan directly after receiving the payment, and the cash will be used as business entertainment expenses for the enterprise.

required:$1.$ Is the above behavior correct and why?

$2.$ What do you think these companies should do$?$

$3.$ Share your opinion on the internal control system for accounts receivable management.