Hello.
30+ companies is no where near enough to start bringing in any significant contracts. You need to be calling hundreds of companies to get a good response. You also need to look at where you are getting the phone numbers from, just calling numbers from the phone book at random will reduce your chances of catching a new contract - your marketing needs to be targeted and seamless; choose an industry e.g. accountants offices, then make a list of all accountants offices within a 10 mile radius of your location, research each one online before calling them (how big are they, do they have an office or work from home, how many employees do they have, are they independent or part of a national group) all these questions will help you decide if they are worth calling or not, then prepare your elevator speech before calling, go through how you want the conversation to go and have one defined goal you want to acheive by the end of the call e.g. get a contact name and number for whoever is incharge of the cleaning.
It is very easy for people to fob you off over the phone and get rid of you, infact if they wanted the could simply just put the phone down - face to face is much harder, they are unlikely to shut the door in your face and people find it harder to lie face to face - get out their with business cards and leaflets knock doors then follow up with a call and email later.
I hope this helps - its all about persistence - do not stop making your calls keep calling, the more calls you make the more likely you are to get a response, and do not get downhearted when you are told they are not interested, use it as a positive can you offer relief cleaning or holiday cover when there cleaner is away this is a great way in and many companies ultimately win contracts by simply providing cover work to begin with.
