* TSX down 28.67 points, or 0.21 percent, to 13,813.25
* Seven of the TSX's 10 main groups rise
TORONTO, Oct 21 (Reuters) - Canada's main stock index see-sawed in morning trade on Wednesday, helped by gains among banks, railways and telecom stocks, while a fall in the price of oil and other commodities pushed energy and mining shares lower.
The most influential gainers included telecom company BCE Inc, which rose 0.9 percent to C$58.05, and Canadian National Railway, which advanced 0.7 percent to C$79.10.
The financials group climbed 0.5 percent, with Toronto-Dominion Bank rising 0.5 percent to C$53.43, and Royal Bank of Canada advanced 0.4 percent to C$74.71.
On the downside, the energy group retreated 1.0 percent and materials, which includes miners, retreated 1.1 percent.
Prices for copper and iron ore are being pressured by weak demand from China.
China's benchmark indexes slumped roughly 3 percent on Wednesday in their worst daily performance in five weeks, while oil prices fell after a big build in U.S. crude inventories exacerbated a global supply-demand imbalance.
At 9:52 a.m. ET (1352 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 28.67 points, or 0.21 percent, to 13,813.25.
Seven of the index's 10 main groups were in positive territory, although decliners outnumbered gainers by 134 to 102, for a 1.31-to-1 ratio on the downside.
Technology company Celestica Inc fell 9.7 percent to C$15.39 after its earnings and outlook missed expectations.
Valeant Pharmaceuticals International Inc continued its recent slide, retreating 2.6 percent to C$184.06.
Reporting by Alastair Sharp; Editing by Nick Zieminski