Times have changed since Covid. There's more reports of this occuring now. Many IOs are using the unofficial yardstick of 180 days in a year. They reckon if you're IN the country more than you're OUT of it, you're not a tourist. Affects mainly those with back to back visa-exempt entries. For some unknown reason there are so many farangs who do sincerely and blindly believe that they're WANTED in Thailand. Sure, TAT want us, but the Royal Thai Police have a different stance. They know when people are working the system, and they've got a lot harder with scrutinising the patterns
Some immigration offices have a policy on this, but it's very hard to maintain and to demonstrate. It's better to choose one method or the other, either 800k in the bank, or transfer 65k per month (which is the better option)
You're being conned. The agent in Thailand has no influence over the embassy in your home country or in your country of residence. As Brandon has said, you get it yourself through eVisa. Also, you do not need to do any border bounces. The 60-day visa can be extended at an immigration office in Thailand.
By "cheap" do you mean a crap policy that doesn't cover you for anything? Or a half-decent policy that you can rely on? Contact this guy for the best advice