EnerBank USA I financed a Systems Pavers Driveway with EnerBank. Been sending payments but no response. Salt Lake City, Utah

We have a new "Systems Pavers' driveway and walkway installed as of May of 2012.  Systems Pavers offered an 18 mo. same as cash finance plan with no interest charged as long as the loan is paid in full by August of 2013.  We are about 40% through it now.  We have been sending $1500.00 each payment and have sent in 5 payments so far.  My concern is that we have never heard a word of acknowledgement from EnerBank since we started making payments.  I have tried contacting them via their phone numbers but no response so far.  I would have expected at least some sort of statement that I could compare my records with theirs.  I am not panicked yet but am developing an impression that the are not very business like in the conduct of their accounts.  I will continue to try to contact them and will update this report as appropriate.  My plan is to pay off the loan completely by around May of 2013.