RPM Receivables Performance Management Balance hit my credit, Will not return messages left, individuals continue to hang up one me when requesting to pay balance, Lynnwood, Washington

 I was not getting service in home where I nanny a 3 and 5 year on the Sprint network. Due to the fact I needed access to my phone in case of emergency I worked with Sprint to get case number and was told early termination fee would be waived. Two employees I spoke to said the tower my phone was hitting had service issues and they did not know when it would be fixed. I was never contacted again by Sprint again. Received a call from RPM regarding issue, paid cell phone balance and they said they would work with Sprint regarding the early termination fee. When I contacted RPM again they said Sprint would not reverse fee however Sprint claims they were never contacted by RPM. I've called weekly for the past 3 months and I either get voice mail, have left messages for them to call back to see what next steps are or, I will get a live person who takes my claim# and says please hold to then be either sent to voice mail or hung-up on. This has a potential to affect my credit and I am trying to work with but I never get a chance to speak with someone, even about paying balance. The one time I spoke to a gentleman to pay cell phone balance he was rude, threatened that I would never get a hold of another person in office and he would make sure my credit was affected. I hold Sprint accountable as well for doing business with a company like this. I have also reported RPM to the Better Business Bureau in Washington and Nationally.