Shares in Altec, the Greek computer company that’s expanding into telecommunications, fell more than 20 percent yesterday after OTE telecom shut down some phone connections leased to it in a payment dispute. Altec sank 22.50 percent to 62 cents, while the Athens bourse’s benchmark general index added 0.18 percent to 3,302.57 points. Earlier in the session, the stock slumped as much as 29 percent, the biggest drop since Altec began trading in 1995, according to Bloomberg data. Altec has a market value of some 62 million euros. OTE telecom, Greece’s former phone monopoly, said last week it temporarily shut down some connections for Altec Telecom, the telecommunications unit, due to overdue payments. Altec plans to appeal to the courts after OTE agreed to a payment of 10.2 million euros and then set a deadline that Altec wasn’t able to meet. «OTE was forced into going ahead with this step since all margins for negotiations had been exhausted,» the Greek telecom company said in a statement. «This step is not illegal and does not consist of an abuse of market power.» The former state telecom monopoly has been gradually losing market share in its fixed line segment since the market’s deregulation in 2001. Shares in OTE, which has a market value of 6.7 billion euros, dropped 0.58 percent, to 13.70 euros, on the Athens Exchange yesterday.