I don't know what is happening here. Because other companies are working OK, I would say that the installation of the programs is fine and the issue is related to something specific in the data. Check data integrity in both AP and BR. Make sure the bank integration is set up correctly in BR, especially that a BR bank is set to 'receive' the transactions posted to that AP bank.

If the batch has been created and is recognized as existing from BR (as you indicated), then AP is likely doing what it needs to, and you should focus your energies on the BR side of things for integration.