Answer:
cash 15,000 debit
   account receivables 15,000 credit
cash  3,000 debit
A/R    5,000 debit
   service revenue 8,000 credit
COGS  6,800 debit
    Merchandise   6,800 credit
Cash  4,000 debit
  A/R               4,000 credit
Cash   2,500 debit
   *unearned revenue   2,500 credit
**utilties payable   800 debit
        cash                   800 credit
salaries expense 3,500 debit
       cash                      3,500 debit
***prepaid expene        375  debit
prepaid insurance   1,125  debit
      cash                             1,500 credit
repairs expense      700 debit
       cash                           700 credit
utilities expense      900 debit
    utilities payable            900 credit
Explanation:
We will record following the debit = credit rule
* It will be considered unearned revenue as we didn'0t perform the services we have the obligation to do so therefore, it is a liability.
**as the expense was recorded previously a payable was created to recognize the obligation to pay our utilities. Therefore, we write-off the payable
*** 1,500 is the full contract value for 4 months:
1,500 / 4 = 375 per month
one most is declared as expense and the remainder as prepaid.