Honestly, I've been through something similar so let me tell you exactly what's happening here.
Yes, the income tax department does track high-value credit card transactions. Under the Annual Information Return (now called AIS — Annual Information Statement), banks are required to report credit card payments exceeding ₹1 lakh per month (cash payments) or aggregate spending above ₹10 lakhs in a year to the IT department. So your HDFC Regalia data is almost certainly sitting in your AIS already. You can check it yourself — log in to incometax.gov.in, go to AIS/TIS section, and see what's reported against your PAN.
Now here's the thing — getting flagged is not the same as getting a notice. The department runs these through algorithms. If your spending is ₹10-11L and your gross income is ₹9.5L, there is a mismatch on paper. But remember your gross income isn't your take-home. You likely paid around ₹1-1.5L in taxes and another chunk in PF. So actual cash in hand over the year was probably ₹7.5-8L. And you spent ₹10-11L on card. That gap will look suspicious to the system.
What saves you is documentation. The relatives-paying-cash-you-swipe thing is actually very common, but you need to show it. Keep WhatsApp messages, UPI receipts, or even a simple written note of who paid you cash and when. If your cousin paid you ₹30k cash and you used the card for their hotel, that's explainable — but only if you can show it.
One thing most people get wrong: they think just because the spending was on legitimate things, they're safe. The IT department doesn't know your spending was legitimate — they only see the number. The burden is on you to explain if asked.
What I'd recommend: right now, download your AIS, cross-check everything, and note down any large transactions that involved cash from others. If you do get a notice under Section 133(6) or 142(1), respond within the deadline with a clear explanation and supporting documents. Don't panic, don't ignore it.
For future years, if amounts are big, have relatives do a UPI transfer to you instead of cash — creates a clean paper trail and saves you this headache entirely.