Learning to read involves so much more then just learning phonics. If phonics instruction was the only solution to reading problems, then, the world would not have to deal with struggling readers at all! With phonics instruction, the methodology is important too. Its not just about making your child go through a Phonic series - popular ones in Malaysia are Peter & Jane and some other off-the rack workbook series.
There are a series of processes involved in learning to read effectively and typically, it will take 12 - 18 months to go from no reading to being able to read independently. Any other rushed methods like 6 week crash courses and 3 month reading programmes will not be effective as most of these will advocate reading by rote.
Very often, parents ask me why no improvement and its been 3 months other teachers are promising reading in 1 or 2 months. Sure, they will to make a few dollars. Be patient, research reading as a skill and you will better understand why reading instruction must be structured and never rushed.
Spelling is closely tied in to the reading ability. If reading was rushed and forced and taught by rote, then spelling will lag way behind. If reading instruction is effective, then the learner will learn to read and spell simultaneously. While it is easier for a child to read on sight, it is not easy to spell on sight. This is a pointer that the reading programme is not effective.
If you child can read, "mat, cat and bat" then, they should also be able to spell the same without difficulties and also be able to spell " sat, rat and hat" without having to be taught them explicitly.