My family and myself have been living in this apt. for 3 yrs. now we want have a bigger place and we had many opportunity's to get a new place and we fill out the app. EVERYTHING SEEMS FINE UNTIL WE GET A PHONE CALL THAT THEY CAN'T RENT TO US B/C WE ARE LATE PAYING RENT AND IS JUST NOT TRUE WE HAVE EVERY RECEIPT TO PROVE THIS
when someone says a lie about someone else-it is legally called
slander. If it is in writing it is called libel.

If it hurts another party, it is grounds for a law suit.
I suggest suing the landlord.

in the mean time, find a small house to buy on a lease-option and
mention that you will not provide credit references…….period.
Why does that matter? If you can prove you paid on time and in full then show the leasing company this information when you apply. Make copies of the canceled checks and receipts and submit them when you apply to rent an apartment. Say to the agent in a nice way, "To make this easier we have included copies of our past rent checks and receipts to show you we pay our rent on time. If there is anything we can do to make this easier then just ask."

If your landlord is lying about you paying rent late, then all the leasing company has to do is refer to your evidence that disputes that. The leasing company will know this guy is lying.
If you're denied credit, you can demand to see the reference on the credit report, or to request a free copy of the credit report, to dispute it.

If it's your present landlord, resolve the issue, if any, ask for a correction, or sue him for slander.
—
Kasey C, PC guru since Apple II days
Where there's a will… I want to be in it.
Request a copy of your resident statement or resident ledger to see exactly which month's they say you were late. May be that may help.
If you have every receipt to prove otherwise….simply show them to the new landlord.