@Navjeet Singh it sounds like you're making a big mistake and you used a very shady agent (unfortunately it is common in this industry.

Common fees will include a set-up fee, a leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

Is this common practice to close a deal? 

If you have a small multifamily (let’s say 4-family apartment) that has a main common entry door into the building, are you supposed to change the lock whenever any tenant moves and then give all the tenants the new key?

Some contracts will restrict the liability to just the guarantor's share or another amount (say 120% of the guarantor's share), but this is less common.

Regarding the mortgage terms, you could either get a flexible loan (not very common) or a 5 year fixed mortgage to reduce the penalty (Vorfälligkeitsentschädigung) when selling the property before the loan ends.

Unfortunately, he made the common mistake of thinking he could borrow his way to wealth.

Common fees will include a set-up fee, leasing fee for each turnover or a lease renewal fee, marking up maintenance, retaining late fees, and more.

Wholesaling is a super common point of entry and with your mind wide open, motivation, and dedication I present this...  

I hope we all have enough common sense to know there is always going to be some outlier market's divergent to the negative or positive given market specific factors.