Immigration Officers visited my apartment building, and my apt.

I applied on Monday for the 90 Visa so I can get the extension for Retirement Visa. Today, Wednesday I got a call from a Lady saying she was the immigration officer and wanted to meet with me at 2pm afternoon. She showed up at 3 pm with another lady officer who was filling in a form, and another tag-along girl who seemed to me to be a trainee.
They interviewed me in the lobby. Took photos of my rental contract, and got the building manager to sign their document. Supposedly it was the building manager confirming she knows me, and I was a resident. Then they got me to sign, but it was all in Thai so I couldn’t understand anything. Then they took a photo of me in front of the building sign, went upstairs, took a photo of me in front of my door, then another photo of me in my apt sitting on my couch. All photos were accompanied by the Lady who called me in the first place. They took a photo of my passport, but rejected taking a photo of my bank account book after I showed her a copy of the Certified letter from my Embassy for retirement income.
They were all very polite and friendly, and at no point did I feel threatened. Seemed like a random check to me. In the evening I told my Girlfriend about it and she is worried that they might be trying to pull off a scam.
Does this all sound normal? Should I be worried?