THIRTY angry sales staff picketed their company's Kowloon store yesterday to demand $500,000 in commission they claimed was owed them. The protest was prompted by Pacific Telecommunication's dismissal of staff who refused to accept a proposal to have the commission paid in three instalments. During yesterday's five-hour sit-in, protesters blocked the entrance to the Yau Ma Tei shop. Spokesman Leung Wai-man said their department head launched a price-reduction campaign three months ago and promised $100 commission for selling each pager which led to a 50 per cent jump in turnover. The company at first refused to pay because the scheme was not authorised but last week offered payment in three instalments as a compromise.