Alliant Credit Union review: Customer service

I had sent a check for almost $40,000 tp pay off a loan. UPS changed the 1st line from a Lockbox ID to just saying Alliant Credit Union/Upstart. I called, emailed and filed complaints and Alliant did nothing to help. When UPS sent supervisors to the Alliant location looking for the overnight letter sent to Alliant, an employee said she could locate it and have it processed that day. She did it in an hour. Alliant told me it's not their fault that UPS changed the lockbox number to just Alliant Credit Union, and then said it could be a very long time to ever find it if they ever do. They signed for the overnight letter and that building is very small. No one cared at Alliant Credit Union / Upstart and I went to the top executive offices at the credit union and Upstart without any help. Then Alliant Credit Union owed me $985 and when I called, an employee said she will have it sent to my checking account within 5-7 days. Today was the 10th day so I called again and was told they send them out around the 30th day after it is owed. Alliant sent me an email saying they were glad an Alliant Credit Union employee resolved the issue, when it was UPS that did. I feel their lack of concern was due to them getting interest until the check was found and processed. I wouldn't recommend Alliatn Credit Union or Upstart.