The Bharti group has dragged the government to TDSAT seeking refund of Rs 135 crore - the entry fee paid by the company for acquiring basic licences - upon migration to the unified access service (UAS) regime.Fearing a "snowballing" effect of the case, the department of telecom (DoT) has shot off a letter to the department of legal affairs seeking approval of the empanelment of three senior advocates and has also clarified that the entry fee was non-refundable."Due to regulatory changes, our basic telecom licences have become redundant. We are, therefore, seeking refund of the entry fee paid by the company," Bharti officials said while confirming that they have moved TDSAT against the government's decision not to refund the money.The government had approved the policy of UAS as per the decision of the cabinet in October 2003. The detailed guidelines envisaged "voluntary" migration of the existing basic and cellular service providers to the new regime."The government has already taken a decision that since the entry fee was non-refundable there is no case for any refund of entry fee as well as any compensation for change of policy, which is a prerogative of the government," DoT said.