The Company maintains cash balances at banks in California and Nevada. Accounts are insured by the Federal Deposit Insurance Corporation up to $250,000 per institution as of June 30, 2015. At times, balances may exceed federally insured limits.

Financial instruments that potentially subject the Company to concentrations of credit risk are primarily trade accounts receivable. The trade accounts receivable are due primarily from business customers over widespread geographical locations within the Local Exchange Carrier (“LEC”) billing areas across the United States. The Company historically has experienced significant dilution and customer credits due to billing difficulties and uncollectible trade accounts receivable. The Company estimates and provides an allowance for uncollectible accounts receivable. The handling and processing of cash receipts pertaining to trade accounts receivable is maintained primarily by three third-party billing companies. The Company is dependent upon these billing companies for collection of its accounts receivable. The billing companies and LEC’s charge fees for their services, which are netted against the gross accounts receivable balance. The billing companies also apply holdbacks to the remittances for potentially uncollectible accounts. These amounts will vary due to numerous factors and the Company may not be certain as to the actual amounts on any specific billing submittal until several months after that submittal. The Company estimates the amount of these charges and holdbacks based on historical experience and subsequent information received from the billing companies. The Company also estimates uncollectible account balances and provides an allowance for such estimates. The billing companies retain certain holdbacks that may not be collected by the Company for a period extending beyond one year. Additionally, certain other billings’ channels consisting of billings submitted to LEC Processors through third parties were discontinued. As such, a significant portion of the receivables at June 30, 2015 and September 30, 2014 pertaining to LEC service providers represent the holdbacks described above.

The Company has concentrations of receivables with respect to certain wholesale accounts and remaining holdbacks with LEC service providers. Three such entities accounted for 26%, 16% and 11% of gross receivables at June 30, 2015 and 23%, 14%, and 10% of gross receivables at September 30, 2014, respectively.