Whoer lit up and told you your mobile IP is on some blacklist. Panic? Not really.
The first thing most antifraud checks do is look your IP up in a reputation database (MaxMind, IP2Location, Scamalytics) and check what kind of ASN it's on. That matters far more than "anonymity level" rating people obsess over. Datacenter IPs get flagged constantly; mobile and residential rarely do, because they're full of real users and churn. iProxy puts you on a real phone with a SIM, so you're in the category that gets a pass by default.
And if one mobile IP does show up dirty, it's usually last-tenant residue that clears with rotation or worst case a switch to another carrier. One "blacklisted" hit on a mobile line is noise, not a verdict.