Lender under writer being difficult

My lenders under writer is being difficult days before closing. I have provided all required documents my debt to income is like 20% with credit score of 850. I have provided all proof of employment pay stubs, tax returns, employment verification documents, 2 ema

ils from my dept. Director, myself and all other staff are annually contracted with new contracts continuing every June for a full year. This is common in this particular work I do. I have shown evidence of prior contracts for the past 5 years and demonstrates I am stable. The under writer is now asking for a letter from my employer stating I have employment “ indefinitely “ which is crazy. I ask the underwriter would your employer give you such a letter? I have researched and can’t find anywhere this is a policy or a regulation required for a loan approval and seems biased to me. I told my loan officer today that I will be reporting this to the agency that regulates lending institutions and he got nervous. Now he’s telling me he will have the president of the bank call me and explain. I believe he will attempt to try and offer me another loan option but with a higher interest rate and I will not be open to that . I feel my rate is locked in and why should I be expected to go with another loan with higher interest. Any opinions or experience in this situation would be appreciated.