Sent iPhone 6 in for $29 battery replacement and received quote for $299 phone replacement--scam???

I sent in my iPhone 6 before the December 31 deadline to get it replaced for $28. I received an email the next day saying the phone was unable to get its batter replaced and I could choose to have it shipped back to me, pay $299 plus tax for them to replace it, or recycle it. When I called Apple to ask why they couldn't replace the battery, no one was able to give me a straight answer! I sent my phone in in perfect condition besides the battery that was dying too quickly (understandable since it is a very old iPhone 6 to have a wonky battery!)

Seems like a scam to me. Even looking online, an iPhone 6 from Best Buy or Walmart is only $99.99--$299 to replace it is obviously a rip-off! Seems like this $29 to get your battery replace is just a ruse for them to up charge you to "replace your phone." I am just hoping when they send my phone back to me, it is still in one piece and they didn't destroy it!