Learn English – What does RA mean

It could mean that the data is erased, or it could imply a more thorough erasure.

The Hacking Lexicon mentions:

Erased data can frequently be retrieved through forensics on the magnetic material of a hard-disk drive or backup tape. So-called "magnetoresistive microscopes" have been developed that painstakingly scour magnetic media, and are able to reconstruct the magnetic image of a disk surface. This will show the faint residue of overwritten data. A common security measure is to "wipe" all traces of the data from a machine. The wiping process usually involves:

• Clearing caches and logfiles. Example include browser caches, cookie files, history logs, and recently used document lists. Note that passwords are often stored in cookies and history URLs.
• Hard-disks "erase" files by simply removing their entries from the directory. The files still exist on the hard-disk. The first step of wiping is to actually erase them by overwriting that area of the disk.
• Overwriting erased areas of the hard-disk at least 7-times (DoD spec) in order to remove all magnetic traces. Forensics specialists can usually read data from a disk that has been overwritten only once.
• Wiping the pagefile. Most programs do this by repeated allocating all possible memory in the system then freeing it, multiple times.

So the true meaning of wipe in the text that you cite might depend on who wrote the sentence – was it authored by a marketer, or a technician? A marketer might use the word wipe even if the company only performs a simple erasure of data on the refurbished hard drives, implying some of the old data could still be read with some sophisticated retrieval techniques. (Or sometimes files just get left on inadvertently.) However, perhaps the company is more careful than that, and the data is meticulously overwritten with 1's and 0's multiple times to prevent any of it from being readable again, even through computer forensics.

Your second guess - "2 months after the first reading" - is correct.

You might have guessed this from context - "set yourself a reminder". You don't need a reminder for something you do continuously.