Well I for one, am pretty pissed off.
Ive spent the last hour and half (between making bottles, making cups of tea, and eating half way through a box of mini egg cakes 
]
In the hope nearing the end the OP had managed to gain the courage, to tell her mother and the rest of the bullies to fook off.
Im not aware of the situation prior to this thread, however, it is clear the OP has not been completely honest, and has lied needlessly previously, when has sent alarm bells ringing.
I was only going to type a bit of moral support for the OP, was also going to type a bit of advice, I noticed from your posts, it was clear you were almost was relying on your DP to put on his superman pants, and Zapp the family issues away.
If this family situation is true, just wanted to say OP [ especially, as it is now clear, that the relationship was finished recently, and DP was called I believe a knob?] this man, may not be around forever. Only you can sort this issue out with your family.
You stated he would answer the phone all day, on the birthday of your mothers. You DP is not always going to be there to answer the phone, maybe you will have a lovely lifelong relationship together, but even if this is the case, he is not going to be sat by the telephone forever.