What can I do about dishonest landlord?

I paid on rent payment on line which my bank verified for my landlord and then when I complained to the coorporate office that this issue needs to be resolved suddenly the office manager has lost my March payment (I have a signed receipt from another staff member) and states she called my bank (without my permissio) and was told that they had no record of the payment. I have been unable to verify she even spoke with anyone and do have the signed letter that was faxed to me and shows the banks fax number so, I do not see how that can be questioned. Any way, now the manager has filed suit to have us evicted even though our rent is paid. I do not know if this is harrassment or what to think. I just need help. Thanks for any feedback you can give.

Sorry I did forget to mention that I live in California. I realize laws are different. Thanks to everyone for the comments so far. I really am not the type to sue however, it did cross my mind that it may be the only option to get a fair resolution. Also, I have verified with the bank that the transaction was completed. The rent was paid via on-line transfer. I have given this to the landlord who stated they were unable to locate it as well as the other payment that I have a signed receipt for. They then told me since they cannot find it I have to pay them immediately. When I refused, as I have proof of payment, and complained to the coorporate office that something had to be done the manager filed the lawsuite. The person who served the papers stated that this complex is his most regular customer and my story sounded much like others. I do not know who those people were. Does anyone know if there is a way to find out if others have had this problem? Any other ideas?

Show up for the appointed hearing with as much evidence as possible. Immediately initiate a counter-suit alleging fraud, harassment, and attempted theft. Unfortunately there's usually not a way to resolve these issues quickly, but if you file suit you might be able to convince your LL to back off in exchange for dropping the suit. Personally, I would find another place to live.

Lawyer up.

Thoughts and prayers are with you! You failed to mention what state or country you live in

get all your documentation in a row, make sure you have originals that you paid, bring that to court on the date and you should win

Call your bank and ask if the rent check was cashed. If it was cashed get a copy and present it to the manager so that they can trace it in their system. If it has not been cashed just stop payment and issue a new one. Thats the easy way.