To see all the contract the company has with a specific Consulting Firm, you have 2 options:
Click "Contracts."

Click "Contracts"

Here, you can manage all the contracts:
To search for a specific provider, you can type it's name on the search field:

Type "kpmg [[enter]]", for instance, You will see all contracts from KPMG
You can also use the filter button to see all the contracts from a provider. Click "Filter":

Click "Select Providers":

Click "Kpmg"

Click "Apply"

Again, you will see all contracts with KMPG:
You can also see only the contracts "In-Progress":
Or the ones "Executed":
B) Go to the Company's page and see all contracts with that firm
To access the company's profile page, click "Panel Management"

Click "Provider Panel"

Click the company you want to see. "Capgemini" in this example:

Click the "Contracts" tab.
You can see all contracts with Capgemini:
you can also find the company using the search bar in the provider panel:
Enter "kpmg", for instance, and hit [Enter]. You will see the company listed:
Click the company name:
Click "Contracts".
You will see all contracts with KPMG: