@Sander95 Contact customer support and keep on contacting them until they reinstate your account.
Once you have been reactivated, turn off instant book if you are going to decline that many guests. With instant book is off, your guests will be "requesting" a stay. A "request" just needs to be answered, NOT approved or declined, even though those buttons are there. So if a guest wants to bring a pet, ANSWER that you are a no pets home and encourage the guest to withdraw their request to book. If the guest wants to bring more people than your property will accommodate, ANSWER that it is too many guests and encourage the guest to withdraw their request to book. Don't decline. You only need to ACCEPT a REQUEST from a guest who meets your expectations.
The major drawback to turning off instant book is that anyone is going to be able to request, and you will still have those people who don't read and don't meet your criteria. You will also be warned by AirBnB that your listing will not appear in the first few pages. So what. You want to get a good handle on how to deal with guests and how to use the platform. Then you can try instant book again.