problem with culture revival & passage - (Jul/04/2006 )

I am having a problem reviving 2 of my cell lines ( MAGI CCR5, a Hela derived cell line & thymocytes). The cells adhere to the flask & multiply ( a round or 2) however they do not reach confluency & cannot be passaged. trypsin/ acutase has no effect. When I tried to use a cell scraper/ lifter to dislodge the cells & innoculate them in new flasks the cells do not attach to the flask but float around.
Suggestions & advice please.

were they old when they were frozen? were they frozen incorrectly? if not, I am not sure why that would happen! I hope you can get it sorted out