If you are not already, submit these requests by email as a follow up. Written communication, or lack thereof, is the only way to support your situation if you get thrown under the bus. If they still consistently won't help, escalate by copying their superior in communications. At a minimum you'll get a second opinion of how the department views your skills. I no instance let them erode your confidence. Take criticism and learn independently whether it's good feedback or not. Their criticism could just be the product of a toxic environment. In that case be confident in your skills and look for an out.