What is meant by "refusal to deal" in the context of agreements related to the sale or purchase of goods or services?

Section 3 Anti-competitive agreements: (4) Any other agreement amongst enterprises or persons including but not restricted to agreement amongst enterprises or persons at different stages or levels of the production chain in different markets, in respect of production, supply, distribution, storage, sale or price of, or trade in goods or provision of services, including- (a) tie-in arrangement; (b) exclusive dealing agreement; (c) exclusive distribution agreement; (d) refusal to deal; (e) resale price maintenance, shall be an agreement in contravention of sub-section (1) if such agreement causes or is likely to cause an appreciable adverse effect on competition in India. Provided that nothing contained in this sub-section shall apply to an agreement entered into between an enterprise and an end consumer. Explanation.--For the purposes of this sub-section,- (d) "refusal to deal" includes any agreement which restricts, or is likely to restrict, by any method the persons or classes of persons to whom goods or services; are sold or from whom goods or services are bought.