Kraken allows monthly 500 000 USD if you are verified. That should be sufficient.
They also have Business accounts with higher limits.
Small exchanges may often allow high limits, but they dont have high volume.
If its a real exchange, only few have filled orderbooks, where an order of more than 5BTC would not let the rate explode.
If its only an exchange service, would you trust anyone who is not really well known, to lend him more than 100k USD?
Remember, If you buy at any exchange, you have to go first!
The exchange service you mentioned, is totally unknown, at least to me.
Its anonymous hosted!
It does not write , where they are, what companyaddress or where registered.
In germany their website is not allowed as it is and would be straight fined.
An exchangecompany that lists 20 faces as employed should be really huge.
But did anyone ever heard of them? Its not listed on coinmarketcap!
To me this is a red flag! I dont give 100k USD to someone who hides himself or maybe usually handles only pocketmoney...
EDIT: Ok, I found some info about coinmama:
https://99bitcoins.com/bitcoin-exchanges/coinmama-review/Fees
The prices you see on Coinmama’s website already include the company’s brokerage service fee of 5.9%. The base price is calculated from TradeBlock’s XBX indexOn top of the stated price, you will need to add a 5% credit card processing fee. This means that Coinmama’s price will be 10.9% above the market rate.
Even if its maybe not a scam, are you really willing to pay that high fees? Why?
I dont know any legit exchange or reseller that is so expensive...its even cheaper to withdraw cash and buy from ATM
Ok, if you pay with creditcard, high fees are common.
But why do you want to buy that high sums using creditcard? Better use sepa or swift. Or buy P2P.