Product: Checking or savings account

Summary of Events : XX/XX/XXXX BMO Alto notified Fraud Detection for amount of {$20000.00} Received a call from Agent XXXX in Fraud for BMO Alto however I was unable to answer the phone. Thereafter, few minutes later, I called back with no answer ( left a voicemail ) I called back to XXXX ( referenced as BMO alto Fraud ) and was redirected back and forth from customer service to Fraud department because BMO is different than BMO alto. Bank now was closed. 
Tuesday XX/XX/XXXX, same issues occur of being redirected back and forth from customer service to fraud department. Finally, they redirect me to XXXX once more. XXXX informs me to unlock my account I need to provide Bank statements on how I funded my account and any transfers associated with that account with ID. I am not provided further details why this is requested, rather it is stated if I do not comply my account will close in XXXX  days. 
I was able to obtain statements from all accounts except my funding account due to it just opening and statements were not available online. I explained to her, its not available she did not believe me. XXXX demanded I not get a screen shot showing the transactions rather she needs the bank statement to show the transactions. I once again elevated that case to my credit union. It took XXXX hours so that I could get that statement. I asked to speak to manager but it was denied. She said they are not available.

No, after statements were provided by my bank, I get a call around XXXX from XXXX saying my account is being closed. She noted she could not disclose the reason but that at this point they no longer wanted to do business with me. I explained that is fine but XXXX  I wanted a reason and XXXX I wanted to know when I would receive my money back. She denied answering and said I would receive a response by mail. She later explained that she would call me back tomorrow ( XX/XX/XXXX ) on the timeframe to obtain my money. I asked to speak to a manager, and it was denied stating they would not say anything different. 

XX/XX/XXXX : I call BMO alto fraud and same back and forth between departments. I am then transferred to XXXX again. She tells me XXXX your account is being closed there is nothing that can be done. I explain again that is fine, I would like to know the reasoning and timeframe to obtain my money. She noted this time she did not find the documentation adequate. I asked what she was looking for and she said it just was not adequate. I exclaimed that I provided the exact statements she requested. She denied that I speak to a manager and she said you account is closing and that is all. 

Later that day, I call again. XXXX states that I need to obtain again, bank statement from my bank and proof of ownership to be able to expedite the return funds request. 

XX/XX/XXXX : XXXX takes back what she said previously, after I paid my bank for the documentation and states again, account is under closure and It will take XXXX weeks to receive funds back. 

She nor anyone at BMO has been able to provide me a clear rational or description of what is going on and why I could not unfreeze my account and obtain my money back. Rather I am given sarcastic questions by the agent, do you know what a high yield savings account is? Do you know what Fraud is?

BMO alto has been extremely unprofessional and have lacked the transparency the consumer requires to work through an issue and see what can be done to resolve the problem as effectively as possible. No formal notification of bank account closure has been provided from their behalf. My bank, XXXX also finds their questioning suspicious. They tried to work with them on a call XX/XX/XXXX but BMO alto refused to work with them.