What is the name of your state? PA
Can a company just decide to suspend the company match to the 401(k) Plan without any warning?
Your company should be offering you an "SPD" - Summary Plan Description. Whomever is listed as the trustee of the plan must provide you with a copy of the complete plan if you ask. There may be a fee for producing a copy of the complete plan.
Details should be listed in the SPD regarding the company match. There is no legal requirement for the company to provide a match, or to provide a 401(k). However, it is common to provide some type of match, and they must follow the formula laid out in the SPD.
Is your 401(k) a weekly contribution ? Or, does your company provide a discretionary % of profit-sharing at the end of each year? Did the company notify you that the Plan was going to change? The company can re-write the Plan to change or eliminate the matching %, but you would/should receive notice if you are a participant in the 401(k) Plan.
-Andy