2. Do I have sufficient legal basis to start a civil action? Will it be possible for my opponent to sue me back in respect of the same case?
Before you start a civil action, you should first consider whether or not you have a sound legal basis for a claim. Apart from considering the legal basis of your claim you should also bear in mind that sometimes both you and your opponent may have respectively committed some faults in relation to the same event. For example, let us say you have entered into a contract to sell some toy cars to your customer. Your customer did not pay you for any of the goods because some of the toy cars manufactured by you were defective. If you start a civil action against your customer to recover the price of the goods sold, your customer may "counterclaim" against you in the same civil action. Your customer might seek monetary compensation from you for any damages which he has suffered due to some of the toys cars which you supplied being defective. If this happens, you may have to face a prolonged lawsuit and may end up gaining nothing.
Therefore, in order to ascertain whether you have any legal basis to start a civil action and in order to assess whether your opponent would have a valid "counterclaim" against you, you should seek legal advice before starting a civil action. You may also consider settling the dispute out of court in order to minimise the legal costs.