Clever Contacts interview questions

I interviewed twice for this company with plenty of call centre experience. I had good rapport and managed to impress the manager interviewing me who seemed very confident I would get the job and be a good fit for the company. The next day after both interviews I got a vague rejection email and upon asking for feedback on why I didn't get the job, they told me they would not be able to give me feedback. I suspect the real reason is either because I worked with one of their competitors in the past or because I was on a working holiday visa, but the fact they would not give me any constructive feedback was not helpful. I would recommend avoiding this company.