So the long and short of it is that I fell out of the job market due to illness in my previous job. Unfortunately, there was certainly a component of mental illness to it (i.e. stress and health-induced anxiety). This was a personally traumatizing and gruesome experience that I'm still processing.
I hadn't been working there for long before falling out, and due to my physical and mental state at the time, I wasn't able to leave on the best of terms. I feel that, at least from my manager and from HR, there is a deep feeling of resentment. I regret not communicating better at the time, but alas the damage is done.
Physically and mentally, I'm feeling better now, so I'm in the process of getting back into the job market and I've been applying for jobs. I got a call back from one of the companies, and the person in question was trying to vet my cv, pressing me to account for the gap in my resumé.
I was unprepared for hardball questions, and in the spirit of honesty I divulged in the moment that I had been out due to illness. They kept digging, wanting a more detailed explanation, which I didn't feel comfortable providing at the time. It's their prerogative to do so of course, but the feeling of being grilled made me less inclined to do so.
Anyhow, I think the person in question got a little suspicious or spooked, so they told me they'd get back to me with some feedback. Today I received an e-mail for them where they state they'd like to continue to interview process but not before I provide them with a reference, specifically at my last place of work, supposedly for ISO compliance.
I'm not at all inclined to go and ask for a reference at my last place of work, and I'm pretty sure I wouldn't even find anyone there who'd write me one.
So is this is it? Should I politely decline? Should I give them more detail? I'm trying to exhaust my options here, but I don't want this episodic lapse to be a permanent blemish on my career.