Threat to take legal action
I have to call your attention to the fact that rent due from you the last four months for the premises occupied by you had not been cleared despite many promises made by you.
I request you once again to clear that same at your earliest, not in any case later than the last day the current month, otherwise I shall be compelled to take such steps as may not be to your liking.
Reply to above
I regret to inform you that the tone of your letter has more than distressed me.
As you know I am one of your oldest tenants and have by now paid your enough money by way of rent to cover the entire cost of building a flat like the one now occupied by me.
Besides, I am experiencing some unexpected financial difficulties now-a-days, but rest assured your rent will be paid, come what may, next month.
I hope you will exercise patience for some time more.