The new strata manager cant roll you over onto a new contract if the old contract has not expired. Just cause they bought a business does not annul the previous contract
If this is a contract renewal, then just dont agree to the conditions you dont like. If the strata manager wont paly ball, then go out and find a new strata manager. You dont have to be locked in to one strata manager and there are plenty out there who do a good job and are not dodgy.
The hardest thing will be to source names of strata managers to approach, but word of mouth or even a google search will help. Then just ask them to tender for your business.