Short answer: you need a tech partner/officer
Long answer:
The model of partnership can be different. The answer depends on your company future vision. Do you want to run a business and pay for everything that's not relevant to your domain or do you want to make the best business possible and crush your competitors?
There is a "Not invented here" principle software companies use to eliminate distracting factors and focus on what matters. However if every software you use isn't good, why not make your own? Plenty of companies do that.
A few options to consider:
1.Software provider
2.1. Re-negotiate software services with current provider. They can be irresponsible, underpaid or bad at negotiation and cannot explain you why they don't want to or cannot provide basic support.
2.2. Find a better software provider. There are plenty of outstaff companies in europe who'll be happy to help you with regular EU wages with a decent quality.
Better to transition slowly if you plan to abadon current contractor. Think of it as a drug use, come off slowly to make it easier.
2. In-house department
2.1. Find a tech lead (freelancer) and start educating one in your domain. Upwork, your network, whatever way is more comfortable for you to find an engineer. Don't worry about sexieness of your business domain, there are plenty of people who'll be willing to help. But one must become an expert in your domain, engineers do what they told to unless you make them understand what your company actually needs, so they can ask you reasonable questions.
2.2. Do you want to start a side software business in 2-5 years? This can be an opportunity for you to run a second/third/Nth company that provides SaaS logistics companies. I don't believe you are the only fish in the logistic sea, neither software providers or engineers are.
Feel free to ping me if you have any questions or need assistance: smart.hope1473@fastmail.com
(I'm in Europe and will be happy to meet over a beer)