Product: Mortgage

I had a very frustrating home purchase experience with Lennar XXXX  and Lennar Mortgage so I want to seek help from you. The home address we put in the offer is XXXX XXXX XXXX XXXX XXXX OR XXXX. 
We entered the deal with good faith because its our second home purchase with Lennar XXXX. We promptly turned in the earnest money check on XX/XX/XXXX and signed the purchase agreement on XX/XX/XXXX. Since Lennar Mortgage can't provide fixed mortgage rates as other builders, I was very concerned about the closing date. However there was only an estimated closing date of XX/XX/XXXX, more than 60 days from the time of signing the agreement and we were unable to lock the interest rate until XX/XX/XXXX. Between the time we signed the agreement ( XXXX ) and the time we were able to lock the interest rate ( XX/XX/XXXX ), the interest rate jumped significantly from 5.375 % to 6.125 % and the calculation for our financials just did not make sense anymore. During that time, Lennar preferred lender Lennar mortgage did not provide any rates information since the 60 days lock in requirement and I felt I was in the dark, unable to do anything but watch the rates climb. We were finally able to lock a 5.875 % interest rate with the help from another loan officer XXXX XXXX when XXXX XXXX was on leave, but there is still a huge gap between the difference between the interest rate of 5.375 % ( the time we signed the purchase agreement and the interest rates we made the decision to purchase ) and 5.875 %. When it comes to numbers, it is {$36000.00}, about 10 % of the home value. We asked for the price reduction of {$15000.00} because the increase of our payment was caused by the unreasonable length of waiting time before the closing date and a lack of corresponding mortgage structure to address that problem. However this request was rejected by Lennar XXXX. At this moment I dont see a good faith from Lennar XXXX to proceed with the deal, and we feel its unfair that we have to pay for the price so we decided not to move forward and Lennar XXXX sent us a termination letter saying that {$4500.00} earnest money will be nonrefundable. I refuse to sign the letter and I hope that you can help me with this issue because the problem is not our fault : 1. Lennar XXXX can't provide a firm closing date until 12 days after we signed the purchase agreement. If they can provide the firm closing date when I signed the purchase agreement, I would have locked in an interest rate of 5.375 %. At the time when they were able to decide on the closing date, the interest rate already climbed and we also passed the time to back out of the deal. This is very unfair to us because of the lack of information. 

2. Lennar Mortgage provided sky high mortgage rates and encouraged us to shop around so they could match. This is extremely time consuming for us and causes confusion later on. Lennar XXXX received the condition approve letter from Lennar Mortgage on XX/XX/XXXX, but I already locked with XXXX XXXX  which promised me with a lower rate and sent email to XXXX at Lennar Mortgage on XX/XX/XXXX, and my loan application with Lennar Mortgage was already canceled in less than 30 days from we original signed the purchase agreement. Because our loan with the XXXX XXXX  fell through, it should trigger the mortgage contingency and we should be able to get our earnest money back. Lennar XXXX  was aware of the change of lender because the XXXX XXXX  ordered my appraisal from XXXX XXXX who is working in the XXXX office. 
I am very serious buyer, and had good experience during our first purchase with Lennar even had same issue that Lennar Mortgage interest rate is sky high, we had spent a lot of effort to shop around then ask Lennar Mortgage if they can match, and house had AC pipe leaking and lighting power off issue, but everything turns out fine, the closing was smooth, so we entered this second deal without any doubt, but this second time really brought me nightmare to force us to back off the deal, we did try to negotiate to keep the deal, but it was rejected by Lennar XXXX, I feel Lennar does not care to lose us, very disappointed. My husband and I was thinking of purchasing more houses from Lennar later, now it looks like we will end the relationship with Lennar. 
Please help refund the earnest money, as I stated above, the problem is not our fault, thank you for your time!