LG VX-8600 / AX-8600

So heres the deal, i had the lg vx7000 for the past year and it was a great phone just wish there was a speaker phone ... but anyways in january our contract ran out (im on a family plan) so we got new phones.. and we eneded up getting the lg vx8600.. and its a great phone i have few complaints about it... except the speakerphone sucking... but now that i have had it for awhile it seems like i dont have the service that i used to have on my 7000.. like im my school i get the ****tiest service ever and i used to have half way decent service... and other areas i dont get service where i used to.. wondering if this is common or something is wrong?