Could tney you say this in a business letter?: To avoid further unpleasantness we recommend you acting at your earliest convenience. ?
The question is what you asked, not what you cited. From a business perspective this letter would not force any action since "at your earliest convenience" leaves when the action is to be performed up to the person. The "earliest convenience" might be next December. This type of letter requires a definitive date - "...we recommend you acting before the fifth of July".