How to convert Protected files (bought in 2005 in one country) to Purchased AAC now that I live in another country?

Hi, I used to live in the US and had bought about 138 songs between 2005 and 2009 on iTunes. I still have these files backed up on my hard drive. After I moved to India, I changed the country on my account. I am unable now to convert the "Protected"/ DRM enabled m4p files into "Purchased" AAC files. When I try to save a file as AAC I get the message "<filename> could not be converted because protected files cannot be converted to other formats".

I tried the procedure described in the iTunes Plus description article as well https://support.apple.com/en-us/HT201616 which suggests: a) Deleting songs eligible for iTunes Plus from the library b) finding them in iTunes store, and c) paying any additional fees (30c a song or something?) and then downloading the DRM free versions.

However, this does not seem to work for me since the songs aren't recognized as purchased items for me (although I'm using the same account/ email all these years).

I am able to listen to the songs from the hard drive backup, but cannot transfer them to any new devices, which is why I thought to convert them in the first place

Help!!