4. Therefore, in order to be entitled to order of reference under section 20, it is necessary that there should be an arbitration agreement and secondly, difference must arise to which this agreement applied. In this case, there is no dispute that there was an arbitration agreement. There has been an assertion of claim by the appellant and silence as well as refusal in respect of the same by respondent. Therefore, a dispute has arisen regarding non-payment of the alleged dues of the appellant. The question is for the present case when did such dispute arise. The High Court proceeded on the basis that the work was completed in 1980 and, therefore, the appellant became entitled to the payment from that date and the cause of action under article 137 arose from that date. But in order to be entitled to ask for a reference under section 20 of the Act there must not only be an entitlement to money but there must be a difference or dispute must arise. It is true that on completion of the work a right to get payment would normally arise but where the final bills as in this case have not been prepared as appears from the record and when the assertion of the claim was made on 28th February, 1983 and there was non-payment, the cause of action arose from that date, that is to say, 28th of February, 1983. It is also true that a party cannot postpone the accrual of cause of action by writing reminders or sending reminders but where the bill had not been finally prepared, the claim made by a claimant is the accrual of the cause of action. A dispute arises where there is a claim and a denial and repudiation of the claim. The existence of dispute is essential for appointment of an arbitrator under section 8 or a reference under section 20 of the Act. See Law of Arbitration by R.S. Bachawat, 1st Edition, page 354. There should be dispute and there can only be a dispute when a claim is asserted by one party and denied by the other on whatever grounds. Mere failure or inaction to pay does not lead to the inference of the existence of dispute. Dispute entails a positive element and assertion in denying, not merely inaction to accede to a claim or a request. Whether in a particular case a dispute has arisen or not has to be found out from the facts and circumstances of the case.