Is it permissible for me to bring other goods into the shop without the company's knowledge, given that it did not adhere to the terms of the contract and caused me harm?

The condition imposed by some merchants on their distributors not to purchase competing goods is void. This is due to the apparent uncertainty (gharar) and ignorance (jahalah) it contains, and the Prophet (peace and blessings be upon him) forbade transactions involving gharar. If the company does not agree to annul this condition, then you must terminate the contract.