CREDO Mobile Zero customer support...Not honoring Apple warranty. San Francisco California

I received an email from CREDO Mobile on 8/6/2015 informing me that the nonfunctioning iPhone I had returned (while still under warranty) needed to have the Find My iPhone feature turned off in order for me to avoid being charged full retail for the replacement phone I had already received. Upon receiving this email, I tried to do as instructed via iCloud, but I was unable to access the Find My iPhone feature from my computer.

Thus, I emailed CREDO Customer Support on 8/7/2015 asking several questions and received a reply later the same day (8/7/2015) letting me know that my inquiry had been forwarded to their Back Office and that someone would be in contact with me to provide further information.

When I still hadn't received any further information from CREDO, I sent a follow up email 8/9/2015. Still no reply, so I submitted additional follow up emails 8/11/2015 and 8/13/2015, but did not hear back from anyone. Finally, after submitting a fourth follow up email on 8/14/2015, I received an email from CREDO later the same day (8/14/2015) to inform me that the broken iPhone had already been shipped back to me, and I was being charged $460 for the replacement.  

In other words, after waiting a week for someone with CREDO Customer Support to provide the information I had requested 8/7/2015 and receiving a response from a CREDO associate 8/7/2015 specifically stating that someone from CREDO would be in touch with me, the only response I ever received was on 8/14/2015 notifying me that the broken iPhone had been returned to me, and that I was being charged $460 for the replacement iPhone even though the returned iPhone was still covered by the Apple warranty.

To add insult to injury, my mobile service was then suspended 8/15/2015 due to the $460 charge on my account. When this occurred, I had to drive across town on my day off to use the phone at my employer's office. Only to be told by the Customer Support Supervisor that there was nothing she could do to reverse the charges and that turning off Find My iPhone and shipping the broken phone back to them wasn't even an option.

The Supervisor readily admitted that they had records of all four of my follow up emails, as well as the email from their own associate stating that someone from CREDO would be in touch with me. But instead of taking responsibility for their lack of follow up and follow through, she tried to blame the Customer Support agent that emailed me on 8/7/2015 and further stated that the associate had misinformed me about someone getting back with me. 

The rationale of CREDO can be summed up as follows: Altough I was told that someone from their Back Office would be in touch with me, and I made numerous follow up attempts, it was my responsibility to call them. Because I didn't call them instead of sending emails, as is their own standard practice, it is entirely my fault that I am being charged $460 for the replacement phone.

Needless to say, I was livid and still am. I refuse to pay $460 for a warranty replacement. This entire debacle could easily be solved if someone from CREDO would assist me in turning off Find My iPhone on the broken phone and allow me to ship it back.

I sent a follow up message to the Customer Support department 8/15/2015 and also left a voice message for the Assistant to the CEO at their corporate headquarters on 8/15/2015. To date, I have not heard from anyone at CREDO, but my mobile service was turned back on 8/16/2015.

The entire lack of appropriate customer service and absence of follow up to assist me in resolving this issue before returning the broken phone to me and charging me for the replacement is totally unethical. Had someone from CREDO contacted me as I repeatedly requested beginning 8/7/2015, answered my questions and walked me through the process of turning off the Find My iPhone feature (even though I don't even know how it was turned on) this entire situation could have been avoided.

If anyone can assist me in resolving this issue, I would greatly appreciate it.