Hello, my name is ***** ***** it is my pleasure to assist you with your question today. How long have you worked there for?
What are you hoping to achieve in this situation?
First of all you may have aimed any comments on FB at family and friends but you must remember that it is still a public forum and you cannot really expect any privacy on there so you must always be careful about what you post. So there is no invasion of privacy if the employer has managed to read these comments through legitimate means (in other words without unlawful access, such as hacking, which is not the case here).
Now, the issue in your situation is that if you have been continuously employed at your place of work for less than 2 years then your employment rights will unfortunately be somewhat limited. Most importantly, you will not be protected against unfair dismissal. This means that your employer can dismiss you for more or less any reason, and without following a fair procedure, as long as their decision is not based on discriminatory grounds (i.e. because of gender, race, religion, age, a disability, sexual orientation, etc.) or because you were trying to assert any of your statutory rights (e.g. requesting maternity/paternity leave, etc.).
If the dismissal had nothing to do with any of the above exceptions then you would not be able to challenge it and your only protection would be if you were not paid your contractual notice period, because unless you were dismissed for gross misconduct, you would be entitled to receive your contractual notice period. If you did not have a written contract in place you would be entitled to the minimum statutory notice period of 1 week. Your employer would either have to allow you to work that notice period and pay you as normal, or they will have to pay you in lieu of notice.
So even if you are treated unfairly and have your correspondence ignored, there is little that can be done to change that from a legal perspective. You can raise a grievance but remember that the employer is able to dismiss you at any point now because you do not have the required service for protection against that. So bear that in mind when you decide on how to approach this.
Hope this clarifies your position? If you could please let me know that would be great, thank you