I learned this the hard way, go down to the redemption department and make sure you let them know who you are and ask they upload papers from you stating any repairs you have made and any proofs of contact. If you have a dishonest taxpayer they do have the option to file an affidavit stating that you, the investor, have not responded to their written request for redemption amounts, they will then be allowed to redeem the property. You could lose your preservation improvements and insurance premiums. You will have to find a lawyer, file a petition, it will get messy, time-consuming and expensive. If you receive a "verification of expenses form", contact the taxpayer and give them the amount needed to redeem that covers your preservation improvements cost and insurance and then take the proof of contact to the redemption department as well. This is not a requirement so ask nicely that they do this and they will, it will prevent the homeowner from circumventing the process. If they do try the office will already have information from you proving that you have contacted the taxpayer and they will not allow the taxpayer to redeem without your signature approving it.
Also, anyone purchasing tax delinquent property in Alabama should really go to Denise Evans website and get her Tax Sale book. Denise's book is worth every penny and then some. If I had purchased this book before I purchased my first tax property I could have saved myself a bit of a headache. Luckily I had it when the taxpayer pulled this nasty stunt. The form I needed to undo the redemption was there in the appendix along with case law and information about the redemption process.